نتایج جستجو برای: sparrows
تعداد نتایج: 1328 فیلتر نتایج به سال:
Previous research has shown heightened recruitment of new neurons to the chickadee hippocampus in the fall. The present study was conducted to determine whether heightened fall recruitment is associated with the seasonal onset of food-storing by comparing neurogenesis in chickadees and a non-food-storing species, the house sparrow. Chickadees and house sparrows were captured in the wild in fall...
Invasive species can displace natives, and thus identifying the traits that make aliens successful is crucial for predicting and preventing biodiversity loss. Pathogens may play an important role in the invasive process, facilitating colonization of their hosts in new continents and islands. According to the Novel Weapon Hypothesis, colonizers may out-compete local native species by bringing wi...
Terrestrial wild birds commonly associated with poultry farms have the potential to contribute to the spread of H5N1 highly pathogenic avian influenza (HPAI) virus within or between poultry facilities or between domesticated and wild bird populations. This potential, however, varies between species and is dependent on several virus and host factors, including habitat utilization, susceptibility...
—We captured 1,055 Nelson’s (Ammodramus nelsoni) and Saltmarsh (Ammodramus caudacutus) sparrows during the winter season (2006–2014) within the outer Coastal Plain of Virginia to determine the composition of subspecies. Birds were captured using mist nets in 24 tidal salt marshes and identified to subspecies using a plumage-based, syntopic key. Contrary to previous assessments, both species of ...
Closely related species of songbirds often show large differences in song syntax, suggesting that major innovations in syntax must sometimes arise and spread. Here we examine the response of male and female swamp sparrows, Melospiza georgiana, to an innovation in song syntax produced by males of this species. Young male swamp sparrows that have been exposed to tutor songs with experimentally in...
BACKGROUND Research on variation in bill morphology has focused on the role of diet. Bills have other functions, however, including a role in heat and water balance. The role of the bill in heat loss may be particularly important in birds where water is limiting. Song sparrows localized in coastal dunes and salt marsh edge (Melospiza melodia atlantica) are similar in size to, but have bills wit...
Shinichi Nakagawa and Joel Pick introduce what we can learn from house sparrows.
BACKGROUND A stable and systematic daily change in light levels at dawn and dusk provides the most reliable indicator of the phase of the day. It is likely that organisms have evolved mechanisms to use these twilight transitions as the primary zeitgeber to adjust their circadian phases. In this study, we investigated under natural illumination conditions the effects of daylight exposure restric...
During times of high energy demand, stored fatty acids are mobilized from adipocytes. This mobilization has previously been shown to be a non-random process, with more hydrophilic fatty acids being mobilized most readily. The objectives of this study were to characterize the relative mobilization of fatty acids from adipocytes in two migratory bird species and to investigate possible changes in...
Male song sparrows sing repertoires of 4–13 distinct song types and have proved a valuable model for testing hypotheses concerning the function and evolution of song complexity. Captive female song sparrows solicit more copulations in response to playback of larger repertoires, yet it remains unclear whether male repertoire size influences female mate choice in natural situations. We used long-...
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