Open Access. Powered by Scholars. Published by Universities.®
- Discipline
Articles 1 - 9 of 9
Full-Text Articles in Life Sciences
Weather And Climate Change Drive Annual Variation Of Reproduction By An Aerial Insectivore, Michael T. Murphy, Lucas J. Redmond, Amy C. Dolan, Nathan W. Cooper, Karen Shepherdson, Christopher Michael Chutter, Sarah Cancellieri
Weather And Climate Change Drive Annual Variation Of Reproduction By An Aerial Insectivore, Michael T. Murphy, Lucas J. Redmond, Amy C. Dolan, Nathan W. Cooper, Karen Shepherdson, Christopher Michael Chutter, Sarah Cancellieri
Biology Faculty Publications and Presentations
For many bird species, but especially aerial insectivores, reproduction depends on weather. Climate change is likely to intensify effects, but with uncertain consequences. We report 22 years of data on Eastern Kingbird (Tyrannus tyrannus) reproduction for two populations located in different hygric environments undergoing climate change; mesic central New York, USA, (NY; 12 years) and xeric southeastern Oregon, USA, (OR: 10 years). Laying date became earlier with increasing temperature in the 30-day period preceding laying in identical fashion at both sites, and in years of early laying, clutch size was larger, length of laying season increased, and failed …
Inter- And Intracontinental Migration By The Eastern Kingbird (Tyrannus Tyrannus), Daniel H. Kim, Lucas J. Redmond, James R. Fox, Michael T. Murphy
Inter- And Intracontinental Migration By The Eastern Kingbird (Tyrannus Tyrannus), Daniel H. Kim, Lucas J. Redmond, James R. Fox, Michael T. Murphy
Biology Faculty Publications and Presentations
We recovered 12 archival geolocators deployed on Eastern Kingbirds (Tyrannus tyrannus) breeding in New York (NY; n¼3, 2 with 2 years of data), Nebraska (NE; n¼6, 1 with 2 years of data), and Oregon (OR; n¼3) to describe migratory routes, timing and rates of migration, nonbreeding season distributions, and migratory connectedness. NY fall migrants migrated along the Atlantic coast to Florida, flew either nonstop across the Gulf of Mexico (GoM; 2 of 3 birds) or stopped once along the way (Cuba and Cayman Islands in different years) to land in Yucatan/Central America. Fall birds from NE and OR arrived at …
Experimental Analysis Of Nest-Site Choice And Its Relationship To Nest Success In An Open-Cup–Nesting Passerine, Sarah Cancellieri, Michael T. Murphy
Experimental Analysis Of Nest-Site Choice And Its Relationship To Nest Success In An Open-Cup–Nesting Passerine, Sarah Cancellieri, Michael T. Murphy
Biology Faculty Publications and Presentations
Nest placement presumably reflects selection for secure sites to minimize failure. Most tests of this hypothesis, however, have failed to support it. We used artificial nests (ARTs) to experimentally evaluate nest-site-choice behavior by an open-cup–nesting bird, the Eastern Kingbird (Tyrannus tyrannus). In 2010 and 2011, we placed ARTs in trees in the riparian zone at Malheur National Wildlife Refuge, Oregon, USA, to test whether (1) characteristics describing the physical location in trees of used and unused ARTs differed, (2) used ART sites more closely resembled naturally chosen sites, (3) successful natural nests (NATs) and successful ARTs were similarly …
The Breeding Biology Of The Northern Pygmy Owl: Do The Smallest Of The Small Have An Advantage?, John F. Deshler, Michael T. Murphy
The Breeding Biology Of The Northern Pygmy Owl: Do The Smallest Of The Small Have An Advantage?, John F. Deshler, Michael T. Murphy
Biology Faculty Publications and Presentations
We explored the breeding biology of the Northern Pygmy-Owl (Glaucidium gnoma) from 2007 to 2009 in a forested reserve in Portland, Oregon. Large body size is often assumed to give animals reproductive advantages, and we tested whether body size affected timing of breeding and examined variation in diet, breeding date, clutch size, and reproductive success to explore whether the presumed benefits of large body size are evident in this species. The average size of 13 clutches was 5.8, and nest success was high (92%); 22 successful nests fledged an average of 5.2 young. Dates of first laying varied …
Lifetime Reproductive Success Of Female Eastern Kingbirds (Tyrannus Tyrannus): Influence Of Lifespan, Nest Predation And Body Size, Michael T. Murphy
Lifetime Reproductive Success Of Female Eastern Kingbirds (Tyrannus Tyrannus): Influence Of Lifespan, Nest Predation And Body Size, Michael T. Murphy
Biology Faculty Publications and Presentations
I report on the lifetime reproductive success (LRS) of female Eastern Kingbirds (Tyrannus tyrannus) in central New York. I investigated the major correlates of LRS and specifi cally tested the hypothesis that small body size yields reproductive benefi ts. Lifetime reproductive success varied widely: 15–20% of females failed to fledge young over their life, whereas 50% of young were fledged by 20% of females. Female lifespan varied between one and eight years, and females that died after one breeding season tended to be smaller-bodied than long-lived females (≥2 seasons). I therefore conducted analyses of LRS for the entire sample and …
Nest Reuse By Eastern Kingbirds: Adaptive Behavior Or Ecological Constraint?, Lucas J. Redmond, Michael T. Murphy, Amy C. Dolan
Nest Reuse By Eastern Kingbirds: Adaptive Behavior Or Ecological Constraint?, Lucas J. Redmond, Michael T. Murphy, Amy C. Dolan
Biology Faculty Publications and Presentations
The reuse of old nests by open-cup nesting passerines is a seemingly rare but potentially adaptive behavior if, as a consequence, females begin to breed earlier, lay larger clutches, or fledge more young. We report an unusually high rate of nest reuse (~10% of 341 nests) for Eastern Kingbirds (Tyrannus tyrannus) breeding at Malheur National Wildlife Refuge, Oregon. We found no difference in availability of nesting habitat or food abundance in territories in which nests were and were not reused. We also found no support for the hypotheses that kingbirds benefited from nest reuse by breeding earlier, laying …
Body Size And Condition, Timing Of Breeding, And Aspects Of Egg Production In Eastern Kingbirds, Michael T. Murphy
Body Size And Condition, Timing Of Breeding, And Aspects Of Egg Production In Eastern Kingbirds, Michael T. Murphy
Biology Faculty Publications and Presentations
Variation in timing of breeding in Eastern Kingbirds (Tyrannus tyrannus) was correlated only weakly with external morphological characters, but was correlated positively and significantly with estimates of body size based on measurements of skeletons and muscle weights. Small females apparently held a reproductive advantage in being able to mobilize resources for reproduction before large females. Egg weight was independent of all measures of female size, but was directly and significantly (P = 0.03) correlated with standard flight muscle weight, a relative index of body condition. Egg size was thus a function more of female body condition than size. On average, …
Nest Success And Nesting Habits Of Eastern Kingbirds And Other Flycatchers, Michael T. Murphy
Nest Success And Nesting Habits Of Eastern Kingbirds And Other Flycatchers, Michael T. Murphy
Biology Faculty Publications and Presentations
Patterns of nest placement and its relationship to nest success in the Eastern Kingbird (Tyrannus tyrannus) were studied in populations breeding in New York and Kansas. Data were augmented with information on nest placement in other open-nesting tyrannids in order to examine the hypothesis that these flycatchers place their nests chiefly so as to conceal them from predators. Nesting success was significantly greater in New York than in Kansas but was relatively high in both populations, as is apparently true of North American breeding flycatchers in general. Geographic variation in nest placement in the Eastern Kingbird was relatively small and …
Clutch Size In The Eastern Kingbird: Factors Affecting Nestling Survival, Michael T. Murphy
Clutch Size In The Eastern Kingbird: Factors Affecting Nestling Survival, Michael T. Murphy
Biology Faculty Publications and Presentations
Observational and experimental procedures were used to evaluate the potential importance of brood size and weather on the evolution of clutch size in the Eastern Kingbird. Modal clutch size was three eggs, yet broods of four were most productive. Nestling size varied inversely with brood size, so that "nestling quality" was lower in broods of four than in broods of three. Asymptotic weight of nestlings in broods of three was directly and significantly correlated with ambient air temperature, followed by hatch order. Because larger broods were being fed during a period of relatively cool and wet weather, the effects of …