Within-season and age-related patterns of reproductive performance in female tree swallows (Tachycineta bicolor)

1988 ◽  
Vol 66 (4) ◽  
pp. 827-834 ◽  
Author(s):  
Bridget J. Stutchbury ◽  
Raleigh J. Robertson
Keyword(s):  
Clutch Size ◽  
Breeding Season ◽  
Reproductive Performance ◽  
Tachycineta Bicolor ◽  
Foraging Efficiency ◽  
Tree Swallows ◽  
Age Classes ◽  
Age Related ◽  
Female Tree ◽  
Second Year

In many species of birds, clutch size decreases as the season progresses, but this is confounded by the fact that young birds not only often have smaller clutches but also breed later than older females. We examined the effect of time of season on clutch size, hatching success, and fledging success of female tree swallows (Tachycineta bicolor) in their second year (SY) and after their second year (ASY), and compared their reproductive performance while controlling for time of season. For both SY and ASY females, clutch size decreased significantly with later first egg dates, which caused number hatched and number fledged per brood to also decline as the season progressed. However, neither the proportion of eggs hatched nor the proportion of young fledged was correlated with first egg date. The within-season decline in clutch size was not due simply to replacement clutches or female age, and we argue that it is also not due to a decrease in food abundance over the breeding season. Age-related differences in reproductive success depended on the time of season. Early in the breeding season, ASY females were superior to SY females in every measure of reproductive performance; however, there were no significant differences between age-classes late in the season. ASY females were more successful than SY females in raising clutches of five or six eggs, which were most common early in the season, but there was no difference between age-classes in raising clutches of four eggs. We suggest that an age-related difference in foraging efficiency and within-season changes in the cost of competition could explain this pattern.

The costs of reproduction in tree swallows (Tachycineta bicolor)

1991 ◽  
Vol 69 (10) ◽  
pp. 2540-2547 ◽  
Author(s):  
Nathaniel T. Wheelwright ◽  
Joanna Leary ◽  
Caragh Fitzgerald
Keyword(s):  
Life History ◽  
Clutch Size ◽  
Brood Size ◽  
Life History Theory ◽  
Tachycineta Bicolor ◽  
Laying Date ◽  
Tree Swallows ◽  
Costs Of Reproduction ◽  
Return Rates ◽  
Trade Offs

We investigated the effect of brood size on nestling growth and survival, parental survival, and future fecundity in tree swallows (Tachycineta bicolor) over a 4-year period (1987–1990) in an effort to understand whether reproductive trade-offs limit clutch size in birds. In addition to examining naturally varying brood sizes in a population on Kent Island, New Brunswick, Canada, we experimentally modified brood sizes, increasing or decreasing the reproductive burdens of females by two offspring. Unlike previous studies, broods of the same females were enlarged or reduced in up to 3 successive years in a search for evidence of cumulative costs of reproduction that might go undetected by a single brood manipulation. Neither observation nor experiment supported the existence of a trade-off between offspring quality and quantity, in contrast with the predictions of life-history theory. Nestling wing length, mass, and tarsus length were unrelated to brood size. Although differences between means were in the direction predicted, few differences were statistically significant, despite large sample sizes. Nestlings from small broods were no more likely to return as breeding adults than nestlings from large broods, but return rates of both groups were very low. Parental return rates were also independent of brood size, and there was no evidence of a negative effect of brood size on future fecundity (laying date, clutch size). Reproductive success, nestling size, and survival did not differ between treatments for females whose broods were manipulated in successive years. Within the range of brood sizes observed in this study, the life-history costs of feeding one or two additional nestlings in tree swallows appear to be slight and cannot explain observed clutch sizes. Costs not measured in this study, such as the production of eggs or postfledging parental care, may be more important in limiting clutch size in birds.

scholarly journals Diverse habitat use during two life stages of the critically endangered Bahama Oriole (Icterus northropi): community structure, foraging, and social interactions

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3500 ◽  
Author(s):  
Melissa R. Price ◽  
William K. Hayes
Keyword(s):  
Habitat Use ◽  
Social Interactions ◽  
Breeding Season ◽  
Pine Forest ◽  
Critically Endangered ◽  
Life Stages ◽  
Vegetation Types ◽  
Age Classes ◽  
Habitat Types ◽  
Second Year

Our ability to prevent extinction in declining populations often depends on effective management of habitats that are disturbed through wildfire, logging, agriculture, or development. In these disturbed landscapes, the juxtaposition of multiple habitat types can be especially important to fledglings and young birds, which may leave breeding grounds in human-altered habitat for different habitats nearby that provide increased foraging opportunities, reduced competition, and higher protection from predators. In this study, we evaluated the importance of three habitat types to two life stages of the critically endangered Bahama Oriole (Icterus northropi), a synanthropic songbird endemic to Andros, The Bahamas. First, we determined the avian species composition and relative abundance of I. northropi among three major vegetation types on Andros: Caribbean pine (Pinus caribaea) forest, coppice (broadleaf dry forest), and anthropogenic areas, dominated by nonnative vegetation (farmland and developed land). We then compared the foraging strategies and social interactions of two age classes of adult Bahama Orioles in relation to differential habitat use. Bird surveys late in the Bahama Oriole’s breeding season indicated the number of avian species and Bahama Oriole density were highest in coppice. Some bird species occurring in the coppice and pine forest were never observed in agricultural or residential areas, and may be at risk if human disturbance of pine forest and coppice increases, as is occurring at a rapid pace on Andros. During the breeding season, second-year (SY) adult Bahama Orioles foraged in all vegetation types, whereas after-second-year (ASY) adults were observed foraging only in anthropogenic areas, where the species nested largely in introduced coconut palms (Cocos nucifera). Additionally, SY adults foraging in anthropogenic areas were often observed with an ASY adult, suggesting divergent habitat use for younger, unpaired birds. Other aspects of foraging (vegetation features, food-gleaning behavior, and food items) were similar for the two age classes. Older Bahama Orioles exhibited relatively higher rates of social interactions (intraspecific and interspecific pooled) in anthropogenic areas, and won more interaction outcomes compared to younger adults. Our findings concur with those of other studies indicating dry broadleaf forest is vitally important to migrating, wintering, and resident birds, including the critically endangered Bahama Oriole, which appears to depend heavily on this vegetation type during certain life stages.

Cavity size, clutch-size and the breeding ecology of Tree Swallows Tachycineta bicolor

Ibis ◽  
2008 ◽  
Vol 135 (3) ◽  
pp. 305-310 ◽  
Author(s):  
WALLACE B. RENDELL ◽  
RALEIGH J. ROBERTSON
Keyword(s):  
Clutch Size ◽  
Tachycineta Bicolor ◽  
Breeding Ecology ◽  
Tree Swallows ◽  
Cavity Size

Experimentally altered plumage brightness of female tree swallows: a test of the differential allocation hypothesis

Behaviour ◽  
2016 ◽  
Vol 153 (5) ◽  
pp. 525-550 ◽  
Author(s):  
Lisha L. Berzins ◽  
Russell D. Dawson
Keyword(s):  
Parental Care ◽  
Brood Size ◽  
Tachycineta Bicolor ◽  
Differential Allocation ◽  
Tree Swallows ◽  
Agonistic Interactions ◽  
Brood Size Manipulation ◽  
Fledging Success ◽  
Female Attractiveness ◽  
Female Tree

The differential allocation hypothesis posits that individuals should invest in the current reproductive attempt according to the attractiveness of their mate, but studies of allocation by males when female traits are manipulated to be more attractive are lacking. In the current study, we experimentally enhanced and reduced the plumage brightness of female tree swallows (Tachycineta bicolor) relative to controls to examine whether males adjust investment in parental care according to female attractiveness, while simultaneously performing a brood size manipulation. Contrary to our predictions, we found no evidence that males provisioned nestlings according to the plumage brightness of females. However, we found that nestling quality and fledging success were lowest when female plumage brightness was reduced and brood size was enlarged. This may be due to the plumage brightness treatment influencing agonistic interactions with other females, and may suggest that plumage brightness is a signal assessed by females.

Clutch size in eastern phoebes (Sayornis phoebe) II: age effects and seasonal variation

1993 ◽  
Vol 71 (9) ◽  
pp. 1738-1742 ◽  
Author(s):  
Kelvin F. Conrad ◽  
Raleigh J. Robertson
Keyword(s):  
Seasonal Variation ◽  
Clutch Size ◽  
Egg Production ◽  
Age Classes ◽  
Female Age ◽  
Linear Decrease ◽  
Double Brooding ◽  
Second Year ◽  
Pattern Of Variation ◽  
Seasonal Decline

We examined seasonal variation in clutch size among single- and double-brooding eastern phoebes to learn how the pattern of variation among female age-classes and early and late-season breeders contributed to overall seasonal variation in clutch size. Clutch sizes of eastern phoebes did not decline predictably (linearly or quadratically) with season when we considered all clutches laid over the season, nor when the first and second clutches of double-brooding birds were each regarded separately. Total seasonal egg production by double-brooding second-year (SY) females declined linearly with season but that of after-second-year (ASY) females did not. Among single-brooding females, which were nearly all SY birds, clutch size, and hence total seasonal egg production, were unaffected by season. In general, SY birds bred later, laid fewer eggs, and were less likely to double-brood than ASY birds. The large seasonal variation in clutch size for the entire population was influenced by two different groups of SY females: (1) double-brooding SY females that nested at the same time as double-brooding ASY birds and had similar clutch sizes, but showed a linear decrease in total seasonal egg production versus initiation date, and (2) single-brooding SY females that nested after double-brooding females, had clutch sizes similar to double-brooding females, and showed no linear decrease in total seasonal egg production versus initiation date. Combined with double-brooding ASY females, these two groups of SY birds increase the variation in clutch size observed on any given day and obscure the pattern of seasonal decline commonly reported for other species.

Food abundance and clutch size of Tree Swallows Tachycineta bicolor

Ibis ◽  
2008 ◽  
Vol 129 ◽  
pp. 243-258 ◽  
Author(s):  
DAVID J. T. HUSSELL ◽  
T. E. QUINNEY
Keyword(s):  
Clutch Size ◽  
Food Abundance ◽  
Tachycineta Bicolor ◽  
Tree Swallows
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