Site- and sex-level differences in adult feeding behaviour and its consequences to offspring quality in tree swallows (Tachycineta bicolor) following brood-size manipulation

2007 ◽  
Vol 85 (8) ◽  
pp. 847-854 ◽  
Author(s):  
D.R. Ardia
Keyword(s):  
New York ◽  
Brood Size ◽  
Feeding Rate ◽  
Tachycineta Bicolor ◽  
Tree Swallows ◽  
Offspring Quality ◽  
Brood Size Manipulation ◽  
Feeding Effort ◽  
Adult Feeding ◽  
Habitat Differences

In species with biparental care, males tend to invest less in offspring than do females, likely because of differences in the costs and benefits associated with parental effort. Here I test for sex differences in the response of tree swallows ( Tachycineta bicolor (Vieillot, 1808)) to a brood-size manipulation at two locations differing in food resources, Alaska and New York. I tested sex and habitat differences in how swallows responded to changes in offspring demand. At both sites, both sexes increased effort when feeding enlarged broods, although Alaskan males increased feeding less than Alaskan females. Males decreased feeding effort more to reduced broods than females, but only in Alaska. Food abundance was higher in Alaska than in New York, and Alaskan tree swallows made more feeding visits than New York tree swallows. In New York, food availability did not predict feeding rate and there was no sex difference in the response to brood manipulation. In both sites, male feeding effort was linked with nestling residual body mass, while female feeding effort was correlated with nestling growth rate. This study demonstrates that male tree swallows differ from females by being the first to reduce feeding effort under certain conditions and that male and female feeding rate affects offspring quality differently.

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.

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 Is Reproduction by Tree Swallows Cost Free?

The Auk ◽  
2000 ◽  
Vol 117 (4) ◽  
pp. 902-912 ◽  
Author(s):  
Michael T. Murphy ◽  
Brian Armbrecth ◽  
Ekaterini Vlamis ◽  
Aaron Pierce
Keyword(s):  
Brood Size ◽  
Egg Production ◽  
Cost Of Reproduction ◽  
Tree Swallows ◽  
Nest Sites ◽  
Early Arrival ◽  
Feeding Effort ◽  
Nestling Period ◽  
Wing Chord ◽  
Site Competition

Abstract We manipulated brood sizes of Tree Swallows (Tachycineta bicolor) in 1996 and 1997 to test for the existence of intra- and intergenerational costs of reproduction. Modal clutch size was six eggs, but experimental brood sizes ranged from two to nine young. Nestling starvation was higher in 1996 (and dependent on brood size) than in 1997, but in both years enlargement of brood size resulted in increased productivity. Nestling mass near fledging was negatively correlated with brood size, but tarsus length and wing chord were not. Food deliveries by parents increased steadily between broods of two to six young but then remained constant between broods of six to nine young. The loss of female mass between incubation and the end of the nestling period was positively related to the pair's total feeding effort, and female mass near fledging declined with increasing brood size. The latter decline disappeared, however, when broods of nine were omitted. Adult return rate (1996 to 1997) was highest among birds that raised enlarged broods. Our results, and a review of other studies of Tree Swallows, suggest that broods of seven or eight young can be raised without costs to the parents or young, and it appears that costs associated with feeding young have not influenced annual fecundity of Tree Swallows. Rather, egg production is most likely limited by energy availability to laying females. A major cost of reproduction for Tree Swallows probably arises from nest-site competition in that early arrival in spring to obtain nest sites exposes adults to high risks of death from starvation.

Benefits of an anti-parasite treatment are influenced by within-brood size variation in Tree Swallows (Tachycineta bicolor)

The Auk ◽  
2020 ◽  
Vol 137 (2) ◽  
Author(s):  
Ilsa A Griebel ◽  
Russell D Dawson
Keyword(s):  
Brood Size ◽  
Herd Immunity ◽  
Relative Size ◽  
Size Variation ◽  
Underlying Mechanism ◽  
Tachycineta Bicolor ◽  
Hatching Asynchrony ◽  
Control Group ◽  
Tree Swallows ◽  
Size Hierarchy

Abstract In all animals, susceptibility to parasites can differ among individuals. Young, nest-bound birds are exposed to a diversity of nest-dwelling ectoparasites that typically feed on their blood. Within broods, hatching asynchrony creates size hierarchies that result in morphological and physiological variation among nest mates, and susceptibility to parasites also may vary predictably with this size hierarchy. Our objective was to use a broad-spectrum, anti-parasite drug, ivermectin (IVM), to treat individual nestling Tree Swallows (Tachycineta bicolor) and assess how nestling susceptibility to parasites varied both within and among broods. Broods were either assigned to an IVM group, where half of the nestlings in a brood received IVM injections and half received control injections of pure sesame oil, or to a control group, where all nestlings received oil injections. We found that the IVM treatment reduced parasite loads for broods as a whole, thereby benefiting all nestlings in IVM broods and suggesting our treatment resulted in herd immunity. Specifically, nestlings from IVM broods had higher hemoglobin concentrations, regardless of whether they received injections with IVM or oil, and greater fledging success, than nestlings from control broods. On the contrary, IVM treatment did not strongly affect nestling morphology, with only marginal effects on the growth rate of ninth primary feathers, and the effects of the treatment on 2 other morphological traits depending on temporal factors. Variation in size within broods, however, influenced the chance of an individual fledging, which increased with relative size within a brood, but only under lower parasite loads (i.e. IVM broods). By experimentally manipulating nestling susceptibility to parasites, we have demonstrated variation in nestling response to an anti-parasite treatment both within and among broods, and future studies should investigate the underlying mechanism for why certain nestlings along the brood size hierarchy are more susceptible to parasites.

Timing of breeding and environmental factors as determinants of reproductive performance of tree swallows

2008 ◽  
Vol 86 (8) ◽  
pp. 843-850 ◽  
Author(s):  
Russell D. Dawson
Keyword(s):  
Reproductive Performance ◽  
Weather Conditions ◽  
Breeding Birds ◽  
Tachycineta Bicolor ◽  
Tree Swallows ◽  
High Quality ◽  
Common Pattern ◽  
Offspring Quality ◽  
Inclement Weather ◽  
Underlying Mechanisms

Decreased reproductive success among birds breeding later in the season is a common pattern in temperate environments, although the underlying mechanisms remain unresolved. The quality hypothesis suggests that high-quality individuals can begin breeding earlier in the season than poorer quality parents, and are also able to invest more in reproduction. Alternatively, the date hypothesis suggests that reduced success among late birds is due to some correlate of date, such as decreased food abundance or offspring value. To test these hypotheses, I manipulated the date that tree swallows, Tachycineta bicolor (Vieillot, 1808), raised offspring by swapping clutches among nests so that birds were raising young either earlier or later than intended, and compared reproductive performance with control nests. My results showed that fledging success was related to the date hypothesis, with later birds being less successful in raising offspring than early breeding birds. Size and mass of offspring were not explained by either hypothesis, but rather by weather conditions experienced prior to measurements being taken. My results highlight the importance of events such as periods of inclement weather that can have significant impacts on offspring quality independently of both date of breeding and parental quality.

Accumulation of PCB Congeners in Nestling Tree Swallows (Tachycineta bicolor) on the Hudson River, New York

2004 ◽  
Vol 38 (23) ◽  
pp. 6240-6246 ◽  
Author(s):  
Kathy R. Echols ◽  
Donald E. Tillitt ◽  
John W. Nichols ◽  
Anne L. Secord ◽  
John P. McCarty
Keyword(s):  
New York ◽  
Hudson River ◽  
Tachycineta Bicolor ◽  
Tree Swallows ◽  
Pcb Congeners
Sign in / Sign up

Export Citation Format

Share Document