House sparrows are small, sexually dimorphic birds in the family Passeridae. The species is one of the most widely distributed and common birds in the world, represented by 12 different subspecies (Summers-Smith, 2009). House sparrows can be found living and breeding in climactically extreme environments from deserts in southern California to cities above the Arctic circle, where they are found almost exclusively in close proximity to human habitation (Hanson et al., 2020b). Considered anthrodependent, some populations have gone extinct locally without human presence (Ravinet et al., 2018; Summers-Smith, 1988). It is for this relationship with people that they received their species identifier domesticus, which derives from the Latin domus or 'house', from Carl Linnaeus in 1758 (Jobling, 2009; Anderson, 2006). Their ubiquity and close association with humans have undoubtedly led to their detailed study across biological and even sociological disciplines. Here, we explore the natural history of house sparrows and the contributions that these birds have made to basic biology and beyond.

House sparrows are native to parts of Asia, North Africa and most of Europe, (with the exception of Italy which is occupied by the Italian sparrow P. italiae; Animation 1). Becoming commensal some 10,000 years ago, house sparrows are now strongly associated with habitats that have been modified by humans. However, they also continue to increase their geographic range by exploiting ongoing and accelerating anthropogenic change (Ravinet et al., 2018; Saetre et al., 2012). A reliance on humans is evident from their colonization of Northern Europe, Eastern Europe and Central Asia in the early 1800s, as agriculture spread and urbanization increased (Summers-Smith, 1963). Though still widespread, significant declines have been reported in the native range of the species since the 1970s. This topic remains contentious (Box 1), but these declines have been attributed to a multitude of factors, including infectious disease, pollution, pesticide use, predator dynamics, new building methodologies and more efficient grain harvesting and storage (Shaw et al., 2008; Summers-Smith, 2003; Singh et al., 2013; Bell et al., 2010; Dadam et al., 2019).

Animation 1

Download asset

House sparrows are one of the most ubiquitous birds in the world (Anderson, 2006). In approximately 170 years, they colonized the globe such that they now reside in every continent except Antarctica and occupy an estimated 76,600,000 km² (Birdlife international, 2018). There have been over 250 introduction or translocation events recorded worldwide (Table 1), with the first deliberate successful introduction occurring in 1851 in New York City (Summers-Smith, 1988). Many introductions stemmed from colonial acclimatization societies purposefully releasing birds for cultural reasons or as failed attempts at biological control. More recently, introductions have been accidental. Ship-assisted dispersal (e.g., cargo ships, cruise liners) has been documented, and other types of vehicle-assisted dispersal are also likely (Sainz‐Borgo et al., 2016; Schrey et al., 2014; Clergeau et al., 2004; Szent-Ivány, 1959; Summers-Smith, 1963).

Male house sparrows tend to be heavier and larger than females (Figure 1; Hanson et al., 2020b). Plumage coloration differs between the sexes. Males have gray crests and black post-ocular stripes with conspicuous white spots behind the eyes (Figure 1b). Male abdomens are gray whereas bills, tails, wings and body feathers are black or dark brown. Plumage in females is drabber, with crests that are dark brown and post-ocular stripes that are light brown. Females lack black head markings and have gray-brown to light brown cheeks, bills and feathers (Figure 1a). Female plumage resembles juveniles and females from other Passer species so much that distinguishing them visually is often difficult (Anderson, 2006). Subspecies also differ in size, mass and male plumage (See Summers-Smith, 1988).

Figure 1

Download asset Open asset

The most conspicuous morphological difference between male and female sparrows is the large black throat badge of males. Arguably, this badge is one of the factors that made this species a model in behavioral ecology (Sánchez-Tójar et al., 2018). Large badge size has been thought to convey an individual’s propensity to win in male-male competitive interactions; the logic was that possessing information a priori about a competitor could save both the badge-holder and his opponents from wasted energy and risk of injury (Rohwer, 1975). Recently, however, the largest meta-analysis to date revealed that badge size is at best an unreliable signal of dominance status (Sánchez-Tójar et al., 2018). The currently favored hypothesis for badge size is that it serves some role in mate choice, as females tend to choose males with large badges, and badge size is positively correlated with male sexual behaviors (Veiga, 1996).

Importantly, many morphological characteristics also vary geographically. Most well-known through the pioneering work of Richard F Johnston and Robert K Selander, plumage color and aspects of body size (wing, tail and tarsus length, skeletal characteristics, and body mass) were found to vary within and between native and introduced populations (Selander and Johnston, 1967; Johnston and Selander, 1964; Johnston and Selander, 1971; Johnston, 1969; Johnston, 1973). Introduced populations in North America were discovered to have pale coloration in hot, arid climates, but darker coloration in cooler, humid climates (Johnston and Selander, 1964). Body size of birds also increased with latitude, and perhaps most interestingly, all of these geographic trends in biological traits arose rapidly in the introduced populations (Johnston and Selander, 1964; Selander and Johnston, 1967; Johnston and Selander, 1971).

Nestling house sparrows are fed an insect-based diet for the first three days after hatching. Later, following fledging, they favor grains, especially outside urban areas (Anderson, 2006). Adult house sparrows have a fairly opportunistic diet throughout much of the year, especially in cities and suburbs where human refuse is plentiful (Summers-Smith, 1988). One of the reasons house sparrows are so adept at exploiting diverse diets might involve plasticity in the release of digestive enzymes (Brzek et al., 2009). Behaviorally, responses to food also seem to play a role in range expansions, another reason this species has been used as a model. For example, house sparrows in the roughly 40-year-old Panama population consume unfamiliar foods more quickly than birds from a much older invasive population in New Jersey in the United States (Martin and Fitzgerald, 2005). A similar pattern is observed among Kenyan sparrows such that birds living at the expanding range edge of that colonization approach and eat novel foods more quickly than birds from the core of the population (Liebl and Martin, 2014).

A tendency to eat novel foods may benefit birds in habitats where resources are scarce or unfamiliar, but such behavior could also come with risks. Spoiled foods or exposure to novel toxins, for example, may activate the immune system (Martin and Fitzgerald, 2005). This notion is supported by the observation that populations differ quite extensively in how their immune systems are organized and what parasites they harbor throughout their lives (Kilvitis et al., 2019; Martin et al., 2015; Martin et al., 2014; Coon and Martin, 2014; Coon et al., 2014).

Sparrows tend to build nests in pre-existing cavities, but they also routinely nest in roofs, eaves and walls of human-built structures (Figure 1c) as well as in densely branched trees and shrubs (Anderson, 2006; Sheldon and Griffith, 2017; Manna et al., 2017). Nests are comprised mostly of vegetation but some clay, sand, cloth and even dung may be used (Heij, 1986). In some cities, nests also contain aromatic plants or even cigarette butts that contain antiparasitic secondary compounds (Sengupta and Shrilata, 1997). Males initially choose nesting sites and subsequently advertise for mates by vocal and visual displays (Summers-Smith, 1963). However, unlike many songbirds, males exhibit aggressive, territorial behavior only in a very small area around the nest site. Females select males based on visual and vocal displays and the location of nest sites (Anderson, 2006). Once paired, males and females often remain together for the entire season or even multiple years. Pairs also commonly use the same nest site for several years (Summers-Smith, 1963), however, as is typical in most bird species, males are more likely to stay in, or habitually return to, the area around a nest site than females (Morrison et al., 2008). Both sexes defend the nest, brood the eggs and care for the young, though females put more effort into the brooding than males (Figure 1d; Anderson, 2006). Pairs are socially monogamous, however, the proportion of offspring that are fathered by an extra-pair male (extra-pair paternity) can reach 26%, particularly if food is scarce and the environment is harsh (Stewart et al., 2015). House sparrows typically begin breeding during the first year of life, but breeding success is comparatively low in younger breeders (Hatch and Westneat, 2007).

Reproductive biology has been another reason this species has been used as a model, in particular to understand the cues that influence the onset of breeding. Towards the global poles, house sparrows, like other species, rely on changes in the number of hours of daylight and temperature to ensure that breeding coincides with peak food availability (Hau, 2001). Nearer to the equator, however, both light levels and temperature are fairly stable year-round (Hau et al., 1998), and house sparrows in this region seem to use changes in precipitation regimes to time breeding. In Panama, India and Malawi, for instance, house sparrows breed predominantly during the dry parts of the year, but in Zambia, sparrows breed both five months prior to the peak of the rains, and again when the rains are ongoing (Nhlane, 2000; Hanson et al., 2020b).

Perhaps the main reason that house sparrows have been a model organism in basic ornithology involves the variation they show in life history and associated physiological traits along gradients in their geographic range. Known as clinal variation, in house sparrows, this phenomenon has been documented for metabolic rates (Hudson and Kimzey, 1966; Kendeigh and Blem, 1974; Blem, 1973), hormone regulation (Romero et al., 2006; Breuner and Orchinik, 2001; Liebl and Martin, 2012), and immune defenses (Kilvitis et al., 2019; Martin and Fitzgerald, 2005; Martin et al., 2004). These trends are best-reflected by clinal variation in clutch size; just as in most songbirds, house sparrow clutches are small near the equator and increase pole-ward (Anderson, 2006). This pattern, which exists in both the native and non-native distribution, is intriguing because of the recency of most introductions. Such recency means that new populations would have had little time for genetic adaptation as well as being exposed to founder effects and other genetic challenges (i.e., bottlenecks) inherent to introductions (Baker, 1995; Lowther, 1977).

Given the broad distribution of the species and its recent arrival in many regions, house sparrows have been used as models of genetic, genomic and more recently epigenetic changes during range expansion. Early studies using allozymes (variants of enzymes encoded by alleles of the same gene) revealed little genetic variation among and within North American populations, but suggested that introduced populations underwent genetic bottlenecks and were significantly differentiated from source and native European populations (Parkin and Cole, 1985; Klitz, 1973). DNA fingerprinting, or minisatellites, was used on house sparrows before any other bird species, and microsatellite research followed soon after, revealing subtler genetic differences among populations (Burke and Bruford, 1987; Neumann and Wetton, 1996). Microsatellite analyses have been valuable to inferring invasion history, population structure and dispersal behavior, as well as establishing relatedness such as parentage (Wetzel et al., 2012; Mock et al., 2012; Schroeder et al., 2013; Jensen et al., 2013; Liker et al., 2009; Schrey et al., 2011; Lima et al., 2012; Schrey et al., 2014; Andrew et al., 2018b; Kekkonen et al., 2011). Critically, it was microsatellite data that provided the genetic evidence of extra-pair paternity in this socially monogamous, pair-bonded species (Griffith et al., 1999).

Recently, an annotated genome became available for house sparrows (Elgvin et al., 2017). The genome belongs to a female house sparrow from a pedigreed, inbred population from the island of Aldra in Norway, and was studied to better understand speciation in the Italian sparrow (P. italiae; Elgvin et al., 2017). The Italian sparrow is a hybrid of the house sparrow and the Spanish sparrow (P. hispaniolensis), and this system has led to a wealth of insight about genetic mechanisms affecting hybrid speciation (Hermansen et al., 2011; Hermansen et al., 2014; Trier et al., 2014; Elgvin et al., 2017; Elgvin et al., 2011). For example, Runemark et al. (2018) investigated the genomes of isolated island populations of the Italian sparrow to understand the formation of hybrid genomes. They found that the contribution of parental genome (in this case, the house sparrow and the Spanish sparrow) can differ greatly across populations, but some genomic regions have less variation than others.

Prior to the annotated genome, a high-density single-nucleotide polymorphism (SNP) array was developed for the species (Hagen et al., 2013; Lundregan et al., 2018). This tool was used to detect signatures of adaptation in introduced populations in climatically varied environments across Australia, and to understand the genetic basis of variation in bill morphology (Andrew et al., 2018a; Lundregan et al., 2018). Other next-generation sequencing tools, such as tissue-specific transcriptomic assemblies, a seminal fluid proteome and a genome-wide linkage map, are also available for the species (Ekblom et al., 2014; Razali et al., 2017; Matsushima et al., 2019; Mirón et al., 2014; Rowe et al., 2020; Hagen et al., 2020).

Epigenetic variation, namely DNA methylation, has also begun to be investigated in house sparrows (Kilvitis et al., 2018; Kilvitis et al., 2019; Riyahi et al., 2017). House sparrows exhibit marked phenotypic variation across introduced populations, even though many non-native populations experienced bottlenecks and founder effects upon introduction (Johnston and Selander, 1971; Liebl and Martin, 2012; Martin et al., 2015; Bókony et al., 2012; Martin and Fitzgerald, 2005; Ben Cohen and Dor, 2018; Hanson et al., 2020b). It has been hypothesized that DNA methylation or other molecular epigenetic mechanisms may have affected the ability of populations to colonize new areas (Box 1). Schrey et al. (2012), for example, found that variation in DNA methylation was inversely correlated with genetic diversity among recently invaded Kenyan populations, suggesting that populations might compensate for low genetic diversity with epigenetic diversity. In Australian house sparrows, a similar pattern was found as well as an epigenetic signature mirroring that of genetic population clustering arising from the original source population (Sheldon et al., 2018). These observations and other data led to the hypothesis that house sparrows might exhibit high epigenetic potential, or the capacity for epigenetic mechanisms within the genome to facilitate phenotypic plasticity (Kilvitis et al., 2017). One form of epigenetic potential is the number of CpG sites (sequences in the genome where DNA methylation can occur) in gene promoters. Indeed, towards the expanding edge of the very recent Kenyan invasion, CpG sites across the genome were significantly higher than in older Kenyan house sparrow populations, suggesting that epigenetic potential may generally mediate the introduction success of the species (Hanson et al., 2020a).

In addition to epigenetic mechanisms, the microbiome could also play an important role in the ecology of the species (Russell et al., 2012; Borre et al., 2014). Gut microbes affect the growth rates of house sparrow nestlings (Kohl et al., 2018), and nestlings and adults differ in the structure and membership of their microbial communities, with the nestling microbial community being affected by social and genetic family affiliation but also diet and environmental microbes (Kohl et al., 2019). Further studies are needed to understand what the microbiome means to the house sparrow, particularly as this bird favors the same areas as humans.

As new technologies are developed and refined, we expect the interest in house sparrow genetics, epigenetics and the microbiome to grow. Several local populations of house sparrows have been pedigreed, which enables quantitative genetic estimates of heritability and genetic architecture (Schroeder et al., 2015; Jensen et al., 2003; Wetzel et al., 2012). Additionally, many museums have large collections of house sparrows including many specimens collected before 1900 (Table 2). These collections will be valuable sources of genetic and morphologic data, as well as for use in analyses of pollutants during different eras of human co-habitation (e.g., DuBay and Fuldner, 2017).

Advocating that house sparrows be used as model organisms is not simple as many definitions of model species are available (Bolker, 2009; Bolker, 2014; Bolker, 2017). This jumble of definitions has led some to claim that 'model' is one of the most under-powered concepts in biology (Katz, 2016). These challenges motivated us to think hard about how house sparrows could serve as models (Bolker, 2009). Besides their historic value in the contexts discussed above (i.e., invasion genetics, behavioral ecology, life history evolution), we feel that they generally promise a high return in basic, practical and even economic insight, a value not attributable to many other species.

Previously, Bedford and Hoekstra (2015) made a form of this argument about the mouse genus Peromyscus. Specifically, they cast the enormous amount of information available for Peromyscus as ideal for modelling intraspecific variation. We are skeptical whether any species can really model variation; there are simply too many interactions possible within genomes, not to mention disparities in the forms and forces of selection and plasticity among populations. We agree, though, that Peromyscus, house sparrows and probably other species could be representative for many small, short-lived and broadly distributed vertebrates that are benefitting from human activity (e.g., urbanization). Moreover, as with Peromyscus species for Lyme disease, Hantavirus and other zoonoses, house sparrows play important roles in local infectious disease risk, including West Nile virus, Salmonella and other infections (Ostfeld et al., 2014; Tizard, 2004; Kilpatrick et al., 2007).

Furthermore, although we and others have tended to focus on them as an exemplary invader, house sparrows also promise insight into the range expansions and contractions of native species, phenomena becoming more common as the global climate continues to change (Box 1). Just like George Box’s claim for mathematical models, no model organism is perfect, but many can be informative (Bolker, 2014; Box, 1976). Although all model organisms will thus have some shortcomings, some, such as the house sparrow, might provide unique value by helping us learn how to mitigate anthropogenic effects on natural areas and systems (Manger, 2008).

All data generated during the preparation of this review are included in the manuscript and the supplementary information is available on figshare (https://doi.org/10.6084/m9.figshare.11915955.v1).

1. 1. Hanson HE
   2. Matthews NS
   3. Hauber ME
   4. Martin LB

   (2020) figshare

   Supplemental Information for "The Natural History of Model Organisms: The House Sparrow in the Service of Basic and Applied Biology".

   https://doi.org/10.6084/m9.figshare.11915955.v1

1. Book

   1. Anderson T

   (2006) Biology of the ubiquitous house sparrow: from genes to populations

   Oxford University Press.

   https://doi.org/10.1093/acprof:oso/9780195304114.001.0001

   • Google Scholar
2. 1. Andrew SC
   2. Jensen H
   3. Hagen IJ
   4. Lundregan S
   5. Griffith SC

   (2018a) Signatures of genetic adaptation to extremely varied australian environments in introduced European house sparrows

   Molecular Ecology 27:4542–4555.

   https://doi.org/10.1111/mec.14897

   • PubMed
   • Google Scholar
3. 1. Andrew SC
   2. Awasthy M
   3. Bolton PE
   4. Rollins LA
   5. Nakagawa S
   6. Griffith SC

   (2018b) The genetic structure of the introduced house sparrow populations in Australia and New Zealand is consistent with historical descriptions of multiple introductions to each country

   Biological Invasions 20:1507–1522.

   https://doi.org/10.1007/s10530-017-1643-6

   • Google Scholar
4. 1. Baker M

   (1995) Environmental component of latitudinal clutch-size variation in house sparrows (Passer domesticus)

   The Auk 112:249–252.

   https://doi.org/10.2307/4088786

   • Google Scholar
5. 1. Bedford NL
   2. Hoekstra HE

   (2015) Peromyscus mice as a model for studying natural variation

   eLife 4:e06813.

   https://doi.org/10.7554/eLife.06813

   • Google Scholar
6. 1. Bell CP
   2. Baker SW
   3. Brooke M
   4. Brooke M
   5. Chamberlain DE

   (2010) The role of the Eurasian sparrowhawk ( Accipiter nisus ) in the decline of the house sparrow ( Passer domesticus ) in Britain

   The Auk 127:411–420.

   https://doi.org/10.1525/auk.2009.09108

   • Google Scholar
7. 1. Ben Cohen S
   2. Dor R

   (2018) Phenotypic divergence despite low genetic differentiation in house sparrow populations

   Scientific Reports 8:394.

   https://doi.org/10.1038/s41598-017-18718-8

   • PubMed
   • Google Scholar
8. Report

   1. Birdlife international

   (2018) Passer domesticus

   The IUCN Red List of Threatened Species.

   https://doi.org/10.2305/IUCN.UK.2017-1.RLTS.T103818789A129643357.en

   • Google Scholar
9. 1. Blem CR

   (1973) Geographic variation in the bioenergetics of the house sparrow

   Ornithological Monographs 14:96–121.

   https://doi.org/10.2307/40168064

   • Google Scholar
10. 1. Bókony V
    2. Kulcsár A
    3. Tóth Z
    4. Liker A

    (2012) Personality traits and behavioral syndromes in differently urbanized populations of house sparrows (Passer domesticus)

    PLOS ONE 7:e36639.

    https://doi.org/10.1371/journal.pone.0036639

    • PubMed
    • Google Scholar
11. 1. Bolker JA

    (2009) Exemplary and surrogate models: two modes of representation in biology

    Perspectives in Biology and Medicine 52:485–499.

    https://doi.org/10.1353/pbm.0.0125

    • PubMed
    • Google Scholar
12. 1. Bolker JA

    (2014) Model species in evo-devo: a philosophical perspective

    Evolution & Development 16:49–56.

    https://doi.org/10.1111/ede.12056

    • PubMed
    • Google Scholar
13. 1. Bolker JA

    (2017) Animal models in translational research: Rosetta Stone or stumbling block?

    BioEssays 39:1700089.

    https://doi.org/10.1002/bies.201700089

    • Google Scholar
14. 1. Borre YE
    2. Moloney RD
    3. Clarke G
    4. Dinan TG
    5. Cryan JF

    (2014) The impact of microbiota on brain and behavior: mechanisms & therapeutic potential

    Advances in Experimental Medicine and Biology 817:373–403.

    https://doi.org/10.1007/978-1-4939-0897-4_17

    • PubMed
    • Google Scholar
15. 1. Box GEP

    (1976) Science and statistics

    Journal of the American Statistical Association 71:791–799.

    https://doi.org/10.1080/01621459.1976.10480949

    • Google Scholar
16. 1. Breuner CW
    2. Orchinik M

    (2001) Seasonal regulation of membrane and intracellular corticosteroid receptors in the house sparrow brain

    Journal of Neuroendocrinology 13:412–420.

    https://doi.org/10.1046/j.1365-2826.2001.00646.x

    • PubMed
    • Google Scholar
17. 1. Brzek P
    2. Kohl K
    3. Caviedes-Vidal E
    4. Karasov WH

    (2009) Developmental adjustments of house sparrow (Passer domesticus) nestlings to diet composition

    Journal of Experimental Biology 212:1284–1293.

    https://doi.org/10.1242/jeb.023911

    • PubMed
    • Google Scholar
18. 1. Burke T
    2. Bruford MW

    (1987) DNA fingerprinting in birds

    Nature 327:149–152.

    https://doi.org/10.1038/327149a0

    • Google Scholar
19. 1. Clergeau P
    2. Levesque A
    3. Lorvelec O

    (2004) The precautionary principle and biological invasion: the case of the house sparrow on the Lesser Antilles

    International Journal of Pest Management 50:83–89.

    https://doi.org/10.1080/09670870310001647650

    • Google Scholar
20. 1. Constable H
    2. Guralnick R
    3. Wieczorek J
    4. Spencer C
    5. Peterson AT
    6. VertNet Steering Committee

    (2010) VertNet: a new model for biodiversity data sharing

    PLOS Biology 8:e1000309.

    https://doi.org/10.1371/journal.pbio.1000309

    • PubMed
    • Google Scholar
21. 1. Coon CA
    2. Brace AJ
    3. McWilliams SR
    4. McCue MD
    5. Martin LB

    (2014) Introduced and native congeners use different resource allocation strategies to maintain performance during infection

    Physiological and Biochemical Zoology 87:559–567.

    https://doi.org/10.1086/676310

    • PubMed
    • Google Scholar
22. 1. Coon CAC
    2. Martin LB

    (2014) Patterns of haemosporidian prevalence along a range expansion in introduced Kenyan house sparrows Passer domesticus

    Journal of Avian Biology 45:34–42.

    https://doi.org/10.1111/j.1600-048X.2013.00235.x

    • Google Scholar
23. 1. Dadam D
    2. Robinson RA
    3. Clements A
    4. Peach WJ
    5. Bennett M
    6. Rowcliffe JM
    7. Cunningham AA

    (2019) Avian malaria-mediated population decline of a widespread iconic bird species

    Royal Society Open Science 6:182197.

    https://doi.org/10.1098/rsos.182197

    • PubMed
    • Google Scholar
24. 1. DuBay SG
    2. Fuldner CC

    (2017) Bird specimens track 135 years of atmospheric black carbon and environmental policy

    PNAS 114:11321–11326.

    https://doi.org/10.1073/pnas.1710239114

    • PubMed
    • Google Scholar
25. 1. Ekblom R
    2. Wennekes P
    3. Horsburgh GJ
    4. Burke T

    (2014) Characterization of the house sparrow (Passer domesticus) transcriptome: a resource for molecular ecology and immunogenetics

    Molecular Ecology Resources 14:636–646.

    https://doi.org/10.1111/1755-0998.12213

    • PubMed
    • Google Scholar
26. 1. Elgvin TO
    2. Hermansen JS
    3. Fijarczyk A
    4. Bonnet T
    5. Borge T
    6. Saether SA
    7. Voje KL
    8. Saetre GP

    (2011) Hybrid speciation in sparrows II: a role for sex chromosomes?

    Molecular Ecology 20:3823–3837.

    https://doi.org/10.1111/j.1365-294X.2011.05182.x

    • PubMed
    • Google Scholar
27. 1. Elgvin TO
    2. Trier CN
    3. Tørresen OK
    4. Hagen IJ
    5. Lien S
    6. Nederbragt AJ
    7. Ravinet M
    8. Jensen H
    9. Sætre GP

    (2017) The genomic mosaicism of hybrid speciation

    Science Advances 3:e1602996.

    https://doi.org/10.1126/sciadv.1602996

    • PubMed
    • Google Scholar
28. 1. Griffith SC
    2. Stewart IRK
    3. Dawson DA
    4. Owens IPF
    5. Burke T

    (1999) Contrasting levels of extra-pair paternity in mainland and island populations of the house sparrow (Passer domesticus): is there an 'island effect'?

    Biological Journal of the Linnean Society 68:303–316.

    https://doi.org/10.1006/bijl.1999.0343

    • Google Scholar
29. 1. Hagen IJ
    2. Billing AM
    3. Rønning B
    4. Pedersen SA
    5. Pärn H
    6. Slate J
    7. Jensen H

    (2013) The easy road to genome-wide medium density SNP screening in a non-model species: development and application of a 10 K SNP-chip for the house sparrow (Passer domesticus)

    Molecular Ecology Resources 13:429–439.

    https://doi.org/10.1111/1755-0998.12088

    • PubMed
    • Google Scholar
30. 1. Hagen IJ
    2. Lien S
    3. Billing AM
    4. Elgvin TO
    5. Trier C
    6. Niskanen AK
    7. Tarka M
    8. Slate J
    9. Saetre GP
    10. Jensen H

    (2020) A genome-wide linkage map for the house sparrow (Passer domesticus) provides insights into the evolutionary history of the avian genome

    Molecular Ecology Resources 20:544–559.

    https://doi.org/10.1111/1755-0998.13134

    • PubMed
    • Google Scholar
31. Preprint

    1. Hanson HE
    2. Chengqi W
    3. Aaron SW
    4. Andrea LL
    5. Rays HY
    6. Lynn BM

    (2020a) Epigenetic potential and DNA methylation in an ongoing house sparrow (Passer domesticus) Range Expansion

    bioRxiv.

    https://doi.org/10.1101/2020.03.07.981886

    • Google Scholar
32. 1. Hanson HE
    2. Zolik JE
    3. Martin LB

    (2020)

    Invasive Birds: Global Trends and Impacts

    Chapter 11: House Sparrow (Passer domesticus Linnaeus, 1758), Invasive Birds: Global Trends and Impacts, CABI.

    • Google Scholar
33. 1. Hatch MI
    2. Westneat DF

    (2007) Age-related patterns of reproductive success in house sparrows Passer domesticus

    Journal of Avian Biology 38:603–611.

    https://doi.org/10.1111/j.0908-8857.2007.04044.x

    • Google Scholar
34. 1. Hau M
    2. Wikelski M
    3. Wingfield JC

    (1998) A neotropical forest bird can measure the slight changes in tropical photoperiod

    Proceedings of the Royal Society of London. Series B: Biological Sciences 265:89–95.

    https://doi.org/10.1098/rspb.1998.0268

    • Google Scholar
35. 1. Hau M

    (2001) Timing of breeding in variable environments: tropical birds as model systems

    Hormones and Behavior 40:281–290.

    https://doi.org/10.1006/hbeh.2001.1673

    • PubMed
    • Google Scholar
36. 1. Heij CJ

    (1986)

    Nests of house sparrows Passer domesticus; Composition and Occupants

    International Study on Sparrows 13:.

    • Google Scholar
37. 1. Hermansen JS
    2. Saether SA
    3. Elgvin TO
    4. Borge T
    5. Hjelle E
    6. Saetre GP

    (2011) Hybrid speciation in sparrows I: phenotypic intermediacy, genetic admixture and barriers to gene flow

    Molecular Ecology 20:3812–3822.

    https://doi.org/10.1111/j.1365-294X.2011.05183.x

    • PubMed
    • Google Scholar
38. 1. Hermansen JS
    2. Haas F
    3. Trier CN
    4. Bailey RI
    5. Nederbragt AJ
    6. Marzal A
    7. Saetre GP

    (2014) Hybrid speciation through sorting of parental incompatibilities in Italian sparrows

    Molecular Ecology 23:5831–5842.

    https://doi.org/10.1111/mec.12910

    • PubMed
    • Google Scholar
39. 1. Hudson JW
    2. Kimzey SL

    (1966) Temperature regulation and metabolic rhythms in populations of the house sparrow, Passer domesticus

    Comparative Biochemistry and Physiology 17:203–217.

    https://doi.org/10.1016/0010-406X(66)90021-1

    • PubMed
    • Google Scholar
40. 1. Jensen H
    2. Saether BE
    3. Ringsby TH
    4. Tufto J
    5. Griffith SC
    6. Ellegren H

    (2003) Sexual variation in heritability and genetic correlations of morphological traits in house sparrow (Passer domesticus)

    Journal of Evolutionary Biology 16:1296–1307.

    https://doi.org/10.1046/j.1420-9101.2003.00614.x

    • PubMed
    • Google Scholar
41. 1. Jensen H
    2. Moe R
    3. Hagen IJ
    4. Holand AM
    5. Kekkonen J
    6. Tufto J
    7. Saether BE

    (2013) Genetic variation and structure of house sparrow populations: is there an island effect?

    Molecular Ecology 22:1792–1805.

    https://doi.org/10.1111/mec.12226

    • PubMed
    • Google Scholar
42. Book

    1. Jobling JA

    (2009)

    Helm Dictionary of Scientific Bird Names

    London: Christopher Helm.

    • Google Scholar
43. 1. Johnston RF

    (1969) Character variation and adaptation in European sparrows

    Systematic Zoology 18:206–231.

    https://doi.org/10.2307/2412605

    • Google Scholar
44. 1. Johnston RF

    (1973) Evolution in the house sparrow. IV. replicate studies in phenetic covariation

    Systematic Biology 22:219–226.

    https://doi.org/10.1093/sysbio/22.3.219

    • Google Scholar
45. 1. Johnston RF
    2. Selander RK

    (1964) House sparrows: rapid evolution of races in North America

    Science 144:548–550.

    https://doi.org/10.1126/science.144.3618.548

    • PubMed
    • Google Scholar
46. 1. Johnston RF
    2. Selander RK

    (1971) Evolution in the house sparrow. ii. adaptive differentiation in North American populations

    Evolution 25:1–28.

    https://doi.org/10.1111/j.1558-5646.1971.tb01855.x

    • Google Scholar
47. 1. Katz PS

    (2016) 'Model organisms' in the light of evolution

    Current Biology 26:R649–R650.

    https://doi.org/10.1016/j.cub.2016.05.071

    • PubMed
    • Google Scholar
48. 1. Kekkonen J
    2. Seppä P
    3. Hanski IK
    4. Jensen H
    5. Väisänen RA
    6. Brommer JE

    (2011) Low genetic differentiation in a sedentary bird: house sparrow population genetics in a contiguous landscape

    Heredity 106:183–190.

    https://doi.org/10.1038/hdy.2010.32

    • PubMed
    • Google Scholar
49. 1. Kendeigh SC
    2. Blem CR

    (1974) Metabolic adaptation to local climate in birds

    Comparative Biochemistry and Physiology Part A: Physiology 48:175–187.

    https://doi.org/10.1016/0300-9629(74)90865-2

    • Google Scholar
50. 1. Kilpatrick AM
    2. LaDeau SL
    3. Marra PP

    (2007) Ecology of West Nile Virus transmission and its impact on birds in the Western Hemisphere

    The Auk 124:1121–1136.

    https://doi.org/10.1093/auk/124.4.1121

    • Google Scholar
51. 1. Kilvitis HJ
    2. Hanson H
    3. Schrey AW
    4. Martin LB

    (2017) Epigenetic potential as a mechanism of phenotypic plasticity in vertebrate range expansions

    Integrative and Comparative Biology 57:385–395.

    https://doi.org/10.1093/icb/icx082

    • PubMed
    • Google Scholar
52. 1. Kilvitis HJ
    2. Ardia DR
    3. Thiam M
    4. Martin LB

    (2018) Corticosterone is correlated to mediators of neural plasticity and epigenetic potential in the hippocampus of Senegalese house sparrows (Passer domesticus)

    General and Comparative Endocrinology 269:177–183.

    https://doi.org/10.1016/j.ygcen.2018.09.014

    • PubMed
    • Google Scholar
53. 1. Kilvitis HJ
    2. Schrey AW
    3. Ragsdale AK
    4. Berrio A
    5. Phelps SM
    6. Martin LB

    (2019) DNA methylation predicts immune gene expression in introduced house sparrows Passer domesticus

    Journal of Avian Biology 50:1965.

    https://doi.org/10.1111/jav.01965

    • Google Scholar
54. 1. Klitz W

    (1973) Empirical population genetics of the North American house sparrow

    Ornithological Monographs 14:34–38.

    https://doi.org/10.2307/40168055

    • Google Scholar
55. 1. Kohl KD
    2. Brun A
    3. Bordenstein SR
    4. Caviedes-Vidal E
    5. Karasov WH

    (2018) Gut microbes limit growth in house sparrow nestlings (Passer domesticus) but not through limitations in digestive capacity

    Integrative Zoology 13:139–151.

    https://doi.org/10.1111/1749-4877.12289

    • PubMed
    • Google Scholar
56. 1. Kohl KD
    2. Brun A
    3. Caviedes-Vidal E
    4. Karasov WH

    (2019) Age-related changes in the gut microbiota of wild house sparrow nestlings

    Ibis 161:184–191.

    https://doi.org/10.1111/ibi.12618

    • Google Scholar
57. 1. Liebl AL
    2. Martin LB

    (2012) Exploratory behaviour and stressor hyper-responsiveness facilitate range expansion of an introduced songbird

    Proceedings of the Royal Society B: Biological Sciences 279:4375–4381.

    https://doi.org/10.1098/rspb.2012.1606

    • Google Scholar
58. 1. Liebl AL
    2. Martin LB

    (2014) Living on the edge: range edge birds consume novel foods sooner than established ones

    Behavioral Ecology 25:1089–1096.

    https://doi.org/10.1093/beheco/aru089

    • Google Scholar
59. 1. Liker A
    2. Bókony V
    3. Kulcsár A
    4. Tóth Z
    5. Szabó K
    6. Kaholek B
    7. Pénzes Z

    (2009) Genetic relatedness in wintering groups of house sparrows (Passer domesticus)

    Molecular Ecology 18:4696–4706.

    https://doi.org/10.1111/j.1365-294X.2009.04363.x

    • PubMed
    • Google Scholar
60. 1. Lima MR
    2. Macedo RH
    3. Martins TL
    4. Schrey AW
    5. Martin LB
    6. Bensch S

    (2012) Genetic and morphometric divergence of an invasive bird: the introduced house sparrow (Passer domesticus) in Brazil

    PLOS ONE 7:e53332.

    https://doi.org/10.1371/journal.pone.0053332

    • PubMed
    • Google Scholar
61. 1. Lowther PE

    (1977) Selection intensity in North American house sparrows (Passer domesticus)

    Evolution 89:302–352.

    https://doi.org/10.2307/2407530

    • Google Scholar
62. 1. Lundregan SL
    2. Hagen IJ
    3. Gohli J
    4. Niskanen AK
    5. Kemppainen P
    6. Ringsby TH
    7. Kvalnes T
    8. Pärn H
    9. Rønning B
    10. Holand H
    11. Ranke PS
    12. Båtnes AS
    13. Selvik LK
    14. Lien S
    15. Saether BE
    16. Husby A
    17. Jensen H

    (2018) Inferences of genetic architecture of bill morphology in house sparrow using a high-density SNP array point to a polygenic basis

    Molecular Ecology 27:3498–3514.

    https://doi.org/10.1111/mec.14811

    • PubMed
    • Google Scholar
63. 1. Manger P

    (2008) Is 21st Century neuroscience too focussed on the rat/mouse model of brain function and dysfunction?

    Frontiers in Neuroanatomy 2:2008.

    https://doi.org/10.3389/neuro.05.005.2008

    • Google Scholar
64. 1. Manna T
    2. Cooper C
    3. Baylis S
    4. Shawkey MD
    5. Waterhouse GIN
    6. Grim T
    7. Hauber ME

    (2017) Does the house sparrow Passer domesticus represent a global model species for egg rejection behavior?

    Journal of Avian Biology 48:346–352.

    https://doi.org/10.1111/jav.01193

    • Google Scholar
65. 1. Martin LB
    2. Pless M
    3. Svoboda J
    4. Wikelski M

    (2004) Immune activity in temperate and tropical house sparrows: a common-garden experiment

    Ecology 85:2323–2331.

    https://doi.org/10.1890/03-0365

    • Google Scholar
66. 1. Martin LB
    2. Coon CAC
    3. Liebl AL
    4. Schrey AW

    (2014) Surveillance for microbes and range expansion in house sparrows

    Proceedings of the Royal Society B: Biological Sciences 281:20132690.

    https://doi.org/10.1098/rspb.2013.2690

    • Google Scholar
67. 1. Martin LB
    2. Liebl AL
    3. Kilvitis HJ

    (2015) Covariation in stress and immune gene expression in a range expanding bird

    General and Comparative Endocrinology 211:14–19.

    https://doi.org/10.1016/j.ygcen.2014.11.001

    • PubMed
    • Google Scholar
68. 1. Martin LB
    2. Fitzgerald L

    (2005) A taste for novelty in invading house sparrows, Passer domesticus

    Behavioral Ecology 16:702–707.

    https://doi.org/10.1093/beheco/ari044

    • Google Scholar
69. 1. Matsushima W
    2. Brink K
    3. Schroeder J
    4. Miska EA
    5. Gapp K

    (2019) Mature sperm small-RNA profile in the sparrow: implications for transgenerational effects of age on fitness

    Environmental Epigenetics 5:1–11.

    https://doi.org/10.1093/eep/dvz007

    • Google Scholar
70. 1. Mirón L
    2. Mira A
    3. Rocha-Ramírez V
    4. Belda-Ferre P
    5. Cabrera-Rubio R
    6. Folch-Mallol J
    7. Cardénas-Vázquez R
    8. DeLuna A
    9. Hernández AL
    10. Maya-Elizarrarás E
    11. Schondube JE

    (2014) Gut bacterial diversity of the house sparrow ( Passer domesticus ) inferred by 16S rRNA sequence analysis

    Metagenomics 3:1–11.

    https://doi.org/10.4303/mg/235853

    • Google Scholar
71. 1. Mock DW
    2. Schwabl H
    3. Schwabl H

    (2012) Alternative matings and the opportunity costs of paternal care in house sparrows

    Behavioral Ecology 23:1108–1114.

    https://doi.org/10.1093/beheco/ars080

    • Google Scholar
72. 1. Morrison EB
    2. Kinnard TB
    3. Stewart IRK
    4. Poston JP
    5. Hatch MI
    6. Westneat DF

    (2008) The links between plumage variation and nest site occupancy in male house sparrows

    The Condor 110:345–353.

    https://doi.org/10.1525/cond.2008.8470

    • Google Scholar
73. 1. Neumann K
    2. Wetton JH

    (1996) Highly polymorphic microsatellites in the house sparrow Passer domesticus

    Molecular Ecology 5:307–309.

    https://doi.org/10.1046/j.1365-294X.1996.00095.x

    • PubMed
    • Google Scholar
74. 1. Nhlane M

    (2000) The breeding biology of the house sparrow Passer domesticus at Balantyre, Malawi

    Ostrich 71:80–82.

    https://doi.org/10.1080/00306525.2000.9639874

    • Google Scholar
75. 1. Ostfeld RS
    2. Levi T
    3. Jolles AE
    4. Martin LB
    5. Hosseini PR
    6. Keesing F

    (2014) Life history and demographic drivers of reservoir competence for three tick-borne zoonotic pathogens

    PLOS ONE 9:e107387.

    https://doi.org/10.1371/journal.pone.0107387

    • PubMed
    • Google Scholar
76. 1. Parkin DT
    2. Cole SR

    (1985) Genetic differentiation and rates of evolution in some introduced populations of the house sparrow, Passer domesticus, in Australia and New Zealand

    Heredity 54:15–23.

    https://doi.org/10.1038/hdy.1985.4

    • Google Scholar
77. 1. Ravinet M
    2. Elgvin TO
    3. Trier C
    4. Aliabadian M
    5. Gavrilov A
    6. Sætre G-P

    (2018) Signatures of human-commensalism in the house sparrow genome

    Proceedings of the Royal Society B: Biological Sciences 285:20181246.

    https://doi.org/10.1098/rspb.2018.1246

    • Google Scholar
78. 1. Razali H
    2. O’Connor E
    3. Drews A
    4. Burke T
    5. Westerdahl H

    (2017) A quantitative and qualitative comparison of illumina MiSeq and 454 amplicon sequencing for genotyping the highly polymorphic major histocompatibility complex (MHC) in a non-model species

    BMC Research Notes 10:346.

    https://doi.org/10.1186/s13104-017-2654-1

    • Google Scholar
79. 1. Riyahi S
    2. Vilatersana R
    3. Schrey AW
    4. Ghorbani Node H
    5. Aliabadian M
    6. Senar JC

    (2017) Natural epigenetic variation within and among six subspecies of the house sparrow, Passer domesticus

    The Journal of Experimental Biology 220:4016–4023.

    https://doi.org/10.1242/jeb.169268

    • PubMed
    • Google Scholar
80. 1. Rohwer S

    (1975) The social significance of avian winter plumage variability

    Evolution 29:593–610.

    https://doi.org/10.2307/2407071

    • Google Scholar
81. 1. Romero LM
    2. Cyr NE
    3. Romero RC

    (2006) Corticosterone responses change seasonally in free-living house sparrows (Passer domesticus)

    General and Comparative Endocrinology 149:58–65.

    https://doi.org/10.1016/j.ygcen.2006.05.004

    • PubMed
    • Google Scholar
82. 1. Rowe M
    2. Whittington E
    3. Borziak K
    4. Ravinet M
    5. Eroukhmanoff F
    6. Sætre GP
    7. Dorus S

    (2020) Molecular diversification of the seminal fluid proteome in a recently diverged passerine species pair

    Molecular Biology and Evolution 37:488–506.

    https://doi.org/10.1093/molbev/msz235

    • PubMed
    • Google Scholar
83. 1. Runemark A
    2. Trier CN
    3. Eroukhmanoff F
    4. Hermansen JS
    5. Matschiner M
    6. Ravinet M
    7. Elgvin TO
    8. Sætre GP

    (2018) Variation and constraints in hybrid genome formation

    Nature Ecology & Evolution 2:549–556.

    https://doi.org/10.1038/s41559-017-0437-7

    • PubMed
    • Google Scholar
84. 1. Russell SL
    2. Gold MJ
    3. Hartmann M
    4. Willing BP
    5. Thorson L
    6. Wlodarska M
    7. Gill N
    8. Blanchet MR
    9. Mohn WW
    10. McNagny KM
    11. Finlay BB

    (2012) Early life antibiotic-driven changes in Microbiota enhance susceptibility to allergic asthma

    EMBO Reports 13:440–447.

    https://doi.org/10.1038/embor.2012.32

    • PubMed
    • Google Scholar
85. 1. Saetre GP
    2. Riyahi S
    3. Aliabadian M
    4. Hermansen JS
    5. Hogner S
    6. Olsson U
    7. Gonzalez Rojas MF
    8. Sæther SA
    9. Trier CN
    10. Elgvin TO

    (2012) Single origin of human commensalism in the house sparrow

    Journal of Evolutionary Biology 25:788–796.

    https://doi.org/10.1111/j.1420-9101.2012.02470.x

    • PubMed
    • Google Scholar
86. 1. Sainz‐Borgo C
    2. Sandra Giner JA
    3. González‐Carcacía S

    (2016)

    Current distribution, habitat use, and breeding records of the house sparrow (Passer domesticus) in Venezuela

    Ornitología Neotropical 27:267–273.

    • Google Scholar
87. 1. Sánchez-Tójar A
    2. Nakagawa S
    3. Sánchez-Fortún M
    4. Martin DA
    5. Ramani S
    6. Girndt A
    7. Bókony V
    8. Kempenaers B
    9. Liker A
    10. Westneat DF
    11. Burke T
    12. Schroeder J

    (2018) Meta-analysis challenges a textbook example of status signalling and demonstrates publication bias

    eLife 7:e37385.

    https://doi.org/10.7554/eLife.37385

    • PubMed
    • Google Scholar
88. 1. Schrey AW
    2. Grispo M
    3. Awad M
    4. Cook MB
    5. McCOY ED
    6. Mushinsky HR
    7. Albayrak T
    8. Bensch S
    9. Burke T
    10. Butler LK
    11. Dor R
    12. Fokidis HB
    13. Jensen H
    14. Imboma T
    15. Kessler-Rios MM
    16. Marzal A
    17. Stewart IRK
    18. Westerdahl H
    19. Westneat DF
    20. Zehtindjiev P
    21. Martin LB

    (2011) Broad-scale latitudinal patterns of genetic diversity among native European and introduced house sparrow (Passer domesticus) populations

    Molecular Ecology 20:1133–1143.

    https://doi.org/10.1111/j.1365-294X.2011.05001.x

    • Google Scholar
89. 1. Schrey AW
    2. Coon CAC
    3. Grispo MT
    4. Awad M
    5. Imboma T
    6. McCoy ED
    7. Mushinsky HR
    8. Richards CL
    9. Martin LB

    (2012) Epigenetic variation may compensate for decreased genetic variation with introductions: a case study using house sparrows ( Passer domesticus ) on two continents

    Genetics Research International 2012:1–7.

    https://doi.org/10.1155/2012/979751

    • Google Scholar
90. 1. Schrey AW
    2. Liebl AL
    3. Richards CL
    4. Martin LB

    (2014) Range expansion of house sparrows (Passer domesticus) in Kenya: evidence of genetic admixture and human-mediated dispersal

    Journal of Heredity 105:60–69.

    https://doi.org/10.1093/jhered/est085

    • PubMed
    • Google Scholar
91. 1. Schroeder J
    2. Cleasby I
    3. Dugdale HL
    4. Nakagawa S
    5. Burke T

    (2013) Social and genetic benefits of parental investment suggest sex differences in selection pressures

    Journal of Avian Biology 44:133–140.

    https://doi.org/10.1111/j.1600-048X.2012.00010.x

    • Google Scholar
92. 1. Schroeder J
    2. Nakagawa S
    3. Rees M
    4. Mannarelli ME
    5. Burke T

    (2015) Reduced fitness in progeny from old parents in a natural population

    PNAS 112:4021–4025.

    https://doi.org/10.1073/pnas.1422715112

    • PubMed
    • Google Scholar
93. 1. Selander RK
    2. Johnston RF

    (1967) Evolution in the house sparrow. I. intrapopulation variation in North America

    The Condor 69:217–258.

    https://doi.org/10.2307/1366314

    • Google Scholar
94. 1. Sengupta S
    2. Shrilata S

    (1997) House sparrow Passer domesticus uses krishnachura leaves as an antidote to malarial fever

    The Emu 97:248–249.

    https://doi.org/10.1071/mu97033

    • Google Scholar
95. 1. Shaw LM
    2. Chamberlain D
    3. Evans M

    (2008) The house sparrow Passer domesticus in urban areas: reviewing a possible link between post-decline distribution and human socioeconomic status

    Journal of Ornithology 149:293–299.

    https://doi.org/10.1007/s10336-008-0285-y

    • Google Scholar
96. 1. Sheldon EL
    2. Schrey A
    3. Andrew SC
    4. Ragsdale A
    5. Griffith SC

    (2018) Epigenetic and genetic variation among three separate introductions of the house sparrow (Passer domesticus) into Australia

    Royal Society Open Science 5:172185.

    https://doi.org/10.1098/rsos.172185

    • PubMed
    • Google Scholar
97. 1. Sheldon EL
    2. Griffith SC

    (2017) A high incidence of non-cavity nesting in an introduced population of house sparrows suggests that the species should not be constrained by cavity-nest site availability

    Avian Research 8:172185.

    https://doi.org/10.1186/s40657-017-0087-0

    • Google Scholar
98. 1. Singh R
    2. Kour DN
    3. Ahmad F
    4. Sahi DN

    (2013)

    The causes of decline of house sparrow (Passer domesticus, Linnaeus 1758) in urban and suburban areas of Jammu region, J & K

    Munis Entomology and Zoology 8:803–811.

    • Google Scholar
99. 1. Stewart IRK
    2. Westneat DF
    3. Barrick RL

    (2015) Food supplementation and extrapair paternity in house sparrows

    The American Midland Naturalist 174:278–289.

    https://doi.org/10.1674/0003-0031-174.2.278

    • Google Scholar
100. Book

     1. Summers-Smith JD

     (1963)

     The House Sparrow (First Ed)

     London: Collins.

     • Google Scholar
101. Book

     1. Summers-Smith JD

     (1988)

     The Sparrows: A Study of the Genus Passer

     A & C Black Publishers Ltd.

     • Google Scholar
102. 1. Summers-Smith JD

     (2003)

     The decline of the house sparrow: a review

     British Birds 96:439–446.

     • Google Scholar
103. 1. Summers-Smith J

     (2009)

     Handbook of the Birds of the World, Volume 14: Bush-Shrikes to Old World Sparrows

     Family Passeridae (Old World Sparrows), Handbook of the Birds of the World, Volume 14: Bush-Shrikes to Old World Sparrows, Lynx Edicions, 10.2989/00306525.2010.519867.

     • Google Scholar
104. 1. Szent-Ivány J

     (1959)

     A háziveréb újabb behurcolása ausztráliába

     Aquila 66:300.

     • Google Scholar
105. 1. Tizard I

     (2004) Salmonellosis in wild birds

     Seminars in Avian and Exotic Pet Medicine 13:50–66.

     https://doi.org/10.1053/j.saep.2004.01.008

     • Google Scholar
106. 1. Trier CN
     2. Hermansen JS
     3. Sætre GP
     4. Bailey RI

     (2014) Evidence for mito-nuclear and sex-linked reproductive barriers between the hybrid Italian sparrow and its parent species

     PLOS Genetics 10:e1004075.

     https://doi.org/10.1371/journal.pgen.1004075

     • PubMed
     • Google Scholar
107. 1. Veiga JP

     (1996) Mate replacement is costly to males in the multibrooded house sparrow: an experimental study

     The Auk 113:664–671.

     https://doi.org/10.2307/4088987

     • Google Scholar
108. 1. Wetzel DP
     2. Stewart IR
     3. Westneat DF

     (2012) Heterozygosity predicts clutch and egg size but not plasticity in a house sparrow population with no evidence of inbreeding

     Molecular Ecology 21:406–420.

     https://doi.org/10.1111/j.1365-294X.2011.05380.x

     • PubMed
     • Google Scholar

Acceptance summary:

The reviewers felt that this was a well-written and entertaining short review on a study species for which "there is surprisingly little general literature". We believe that the article will make a strong contribution to "The Natural History of Model Organisms" collection.

Decision letter after peer review:

Thank you for submitting your article for consideration by eLife. Your article has been favourably reviewed by two peer reviewers, and the evaluation has been overseen by Stuart King as the Associate Features Editor. The following individual involved in review of your submission has agreed to reveal their identity: Mark Ravinet (Reviewer #1). The editor has drafted this decision to help you prepare a revised submission.

Summary:

This essay is being considered as part of a series of articles on "The Natural History of Model Organisms" (https://elifesciences.org/collections/8de90445/the-natural-history-of-model-organisms). Each article should explain how our knowledge of the natural history of a model organism has informed recent advances in biology, and how understanding its natural history can influence/advance future studies.

This specific article provides a summary of our current knowledge on the biology and evolution of the house sparrow, and discusses its place as a model species for biological insight. Both reviewers were very positive about the article, finding it to be a well-written and entertaining short review on a study species for which "there is surprisingly little general literature (with the exception of a few rather niche books)". Reviewer 1 noted, "I learned quite a bit and I am grateful to the authors for pointing me towards some useful references I should add to my reading list".

Neither reviewer had any major concerns, but they did make a few suggestions that could strengthen the article. These mostly relate to refining the focus of the text, while one relates to the tables included in the article.

Suggested revisions:

1) Invasion biology

Since, invasion biology distinguishes the house sparrow from the other model organisms included in the eLife collection thus far, the reviewers wondered if the text could be reorganized slightly to make this theme more prominent. The general feeling was that this could be achieved by simply renaming some of the sections and adding a few guiding sentences throughout.

2) Epigenetic basis of phenotypic plasticity

The article gives a lot of detail on the epigenetic basis of phenotypic plasticity in house sparrows. This is not that surprising given a lot of the work on the system is done by the authors. The reviewers, however, felt it would be better to balance this with a bit more on the recent evolutionary genomics on the species. For example, the Italian sparrow is mentioned only in passing but it is quite an important aspect of why this study system is so interesting to speciation research. Work by Elgvin et al., 2017 and 2011, Hermansen et al., 2014, and Trier et al., 2014 is worth looking at.

3) Conclusion

The reviewers thought the conclusion would be stronger if it simply focused on the strengths of the house sparrow as a study organism, and the questions that may be best answered with this species in the future. The sentences agreeing and disagreeing with the Peromyscus article should probably be removed. Different model organisms are best suited for answering different questions, and all model organisms have shortcomings.

4) Tables

Please add references to both tables make it clear where the data came from. This could be done by adding an extra column to each table for the relevant citations. Alternatively, if you opt to upload the original datasets you compiled (and related references) to a repository such as Figshare, you could simply cite the dataset in the captions for the tables. Please also provide more detail about Table 2 to make it clear whether your search was focused on North American collections, or whether the search was more widespread and all the collections just happen to be in North America by chance.

Suggested revisions:

1) Invasion biology

Since, invasion biology distinguishes the house sparrow from the other model organisms included in the eLife collection thus far, the reviewers wondered if the text could be reorganized slightly to make this theme more prominent. The general feeling was that this could be achieved by simply renaming some of the sections and adding a few guiding sentences throughout.

We agree that the house sparrow is an extraordinarily successful invasive species, and we highlight this aspect of its natural history throughout the manuscript. But to exclusively discuss this aspect only may detract from other elements of the natural history, behavior, morphology, and physiology that have also been important (e.g., badges as ornaments, biorhythms, geographic variation in metabolic rates and body size). For these reasons, we chose not to reorganize.

2) Epigenetic basis of phenotypic plasticity

The article gives a lot of detail on the epigenetic basis of phenotypic plasticity in house sparrows. This is not that surprising given a lot of the work on the system is done by the authors. The reviewers, however, felt it would be better to balance this with a bit more on the recent evolutionary genomics on the species. For example, the Italian sparrow is mentioned only in passing but it is quite an important aspect of why this study system is so interesting to speciation research. Work by Elgvin et al., 2017 and 2011, Hermansen et al., 2014, and Trier et al., 2014 is worth looking at.

We agree and have included an additional paragraph about hybrid speciation of the Italian sparrow including the requested citations. We consider to have now balanced the genomic elements with the epigenetic elements in our discussion.

3) Conclusion

The reviewers thought the conclusion would be stronger if it simply focused on the strengths of the house sparrow as a study organism, and the questions that may be best answered with this species in the future. The sentences agreeing and disagreeing with the Peromyscus article should probably be removed. Different model organisms are best suited for answering different questions, and all model organisms have shortcomings.

We agree that all model organisms have shortcomings, and indeed, we worry that the concept of model organism has taken on so many meanings recently that the term has started to lose its utility. To make this case and emphasize the relevant value of house sparrows as a particular type of model, we feel that we need to juxtapose it with more traditional model organisms. This approach also justifies important areas of future study for our focal species.

4) Tables

Please add references to both tables make it clear where the data came from. This could be done by adding an extra column to each table for the relevant citations. Alternatively, if you opt to upload the original datasets you compiled (and related references) to a repository such as Figshare, you could simply cite the dataset in the captions for the tables. Please also provide more detail about Table 2 to make it clear whether your search was focused on North American collections, or whether the search was more widespread and all the collections just happen to be in North America by chance.

We have made the sources used to produce the figures and the tables available on Figshare with the DOI embedded in the caption. Further, we made the extended version of Table 2 available and included the date of the search and all search terms used to compile the table. We also updated the caption to reflect that all institutions with data in the VertNet database were included in the production of the table. We updated Table 2, as well.

Author details

1. Haley E Hanson

   Haley E Hanson is in the Global and Planetary Health strategic area at the University of South Florida, Tampa, United States

   Contribution

   Visualization, Writing - original draft, Writing - review and editing

   For correspondence

   haleyehanson@gmail.com

   Competing interests

   No competing interests declared

   "This ORCID iD identifies the author of this article:" 0000-0002-0513-5911

2. Noreen S Mathews

   Noreen S Mathews is in the Global and Planetary Health strategic area at the University of South Florida, Tampa, United States

   Contribution

   Visualization, Writing - review and editing

   Competing interests

   No competing interests declared

3. Mark E Hauber

   Mark E Hauber is in the Department of Evolution, Ecology and Behavior, School of Integrative Biology, University of Illinois at Urbana-Champaign, Urbana and Champaign, United States

   Contribution

   Conceptualization, Writing - original draft, Writing - review and editing

   Competing interests

   No competing interests declared

4. Lynn B Martin

   Lynn B Martin is in the Global and Planetary Health strategic area at the University of South Florida, Tampa, United States

   Contribution

   Conceptualization, Supervision, Writing - original draft, Writing - review and editing

   Competing interests

   No competing interests declared

• 12,321

  views

• 538

  downloads

• 30

  citations

Views, downloads and citations are aggregated across all versions of this paper published by eLife.