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Abstract Urbanization is one of the most extreme forms of land transformation and results in changes to ecosystems and species compositions. As a result, there are strong directional selection pressures compared to nearby rural areas. Despite a surge in research on the different selection pressures on acoustic communication in urban and rural areas, there has been comparatively little investigation into traits involved with visual communication. We measured the plumage of museum specimens of white-crowned sparrows (Zonotrichia leucophrys) from urban and adjacent rural habitats in San Francisco, CA, to assess the effects of divergent habitats on plumage. We found significant differences in dorsal plumage, but not crown plumage, between urban and rural populations that have been diverging over the past 100 years. Urban birds have increasingly darker and duller dorsal plumage, whereas rural birds in adjacent areas have plumage with richer hues and more color complexity. Our findings suggest a newly observed adaptation to urban environments by native species and suggest that many traits, in addition to acoustic signals, may be changing in response to urban selection pressures. Additional collections in urban areas are needed to explore likely divergences in plumage coloration between urban and rural environments.
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No difference in reproductive investment or success across urban and rural breeding pairs in an urban-adapted songbird
ABSTRACT Species classified as “urban-adapters” are often assumed to thrive in cities because they are commonly found across the urbanization gradient. However, urban-living populations of many urban-adapted species have been found to have lower reproductive success relative to their rural counterparts. Sturnus vulgaris (European Starling) is a common urban-adapted species found across most of the globe. While S. vulgaris have lowered reproductive success in urban areas in their native range, less is known about how urbanization impacts reproduction in their invasive ranges. We tested for differences in reproductive investment and success across urban and rural S. vulgaris populations in Georgia, which is part of their North American invasive range. We found few differences in reproductive output for urban vs. rural S. vulgaris—clutch size, egg mass, egg volume, incubation behavior, provisioning rates, brooding behavior, and nestling wing chord were all similar across S. vulgaris populations from more urban and more rural study sites. Although urban birds produced a higher number of hatchlings and rural birds produced young in higher body condition, neither of these factors influenced reproductive success because the number of fledglings produced were similar for urban and rural breeding S. vulgaris. Overall, S. vulgaris in their invasive range performed similarly well in more urban vs. more rural habitats. Future work should explore whether urbanization affects other components of fitness in starlings (e.g., adult survival).
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- Award ID(s):
- 2217429
- PAR ID:
- 10566208
- Publisher / Repository:
- Oxford
- Date Published:
- Journal Name:
- Ornithology
- ISSN:
- 0004-8038
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1093/ornithology/ukae047
