Avian Incubation Patterns Reflect Temporal Changes in Developing Clutches

Cooper, Caren B.; Voss, Margaret A.

doi:10.1371/journal.pone.0065521

Cited by 66 publications

(72 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In addition, small‐scale variation in incubation temperature has been reported to have significant effects on embryo development (Hepp, Kennamer & Johnson ) and egg temperatures are normally maintained at a higher, and less variable, level closer to hatch (Webb ). This involves changes in on‐off bouts by females with no increase in the total time incubating, consistent with the hypothesis that embryo thermal tolerances narrow as embryo's age (Cooper & Voss ). Potentially, our PHZ treatment interfered with this ‘typical’ female behaviour towards the end of incubation.…”

Section: Discussionsupporting

confidence: 82%

Experimental reduction of haematocrit affects reproductive performance in European starlings

2015

View full text Add to dashboard Cite

Summary Given the function of haemoglobin and observed increases in haematocrit during periods of increased energetic demands, haematocrit and haemoglobin are assumed to be related to aerobic capacity. Reductions in haematocrit and haemoglobin during reproduction are similar in magnitude to increases associated with aerobically demanding activities, and therefore, we sought to investigate whether these reductions in haematology have consequences for reproductive performance. We analysed associations between natural variation in haematology in free‐living European starlings (Sturnus vulgaris) and reproductive performance. To test whether transient reductions in haematology during different stages of reproduction (egg production and late incubation/early chick rearing) affected measures of reproductive performance, we also manipulated haematology using phenylhydrazine (PHZ), which lyses red blood cells. To investigate effects of reductions of haematology during egg‐laying, we treated females with PHZ or saline (control) upon completion of their unmanipulated first clutch and removed eggs to induce the production and rearing of a replacement clutch. To investigate effects of reductions of haematology during chick rearing, we treated females during incubation of the unmanipulated first clutch and then monitored the subsequent hatching and rearing of the clutch. Individuals with higher haematocrit and haemoglobin initiated nesting earlier. Furthermore, higher haemoglobin levels during incubation were associated with a greater number of chicks fledged. PHZ treatment prior to egg production resulted in a significant delay in the laying of replacement clutches, but had no effect on provisioning rate or the size or number of chicks fledged. PHZ treatment during incubation and early chick rearing resulted in decreased hatchling mass in all years and a decrease in the size and number of fledglings in one of 2 years. The year that the effect of PHZ was observed appeared to be a particularly difficult year, as hatchling mass, brood size at hatching and at fledging were low among control females compared to other years. Our results suggest that a reduction in haematology during reproduction can be functionally significant, but that these costs are context‐dependent.

show abstract

Section: Discussionsupporting

confidence: 82%

Experimental reduction of haematocrit affects reproductive performance in European starlings

2015

View full text Add to dashboard Cite

show abstract

“…Separate linear mixed-effects models were used to determine if activity onset was related to first egg of the season for individual dark-eyed juncos and great tits (hereafter referred to as egg 1 date), the day of incubation squared (Cooper and Voss 2013), and date of data collection (included as fixed effects). Year (for dark-eyed juncos) and nest ID were included as random effects.…”

Section: Statistical Analysesmentioning

confidence: 99%

Early to rise, early to breed: a role for daily rhythms in seasonal reproduction

et al. 2017

View full text Add to dashboard Cite

Vertebrates use environmental cues to time reproduction to optimal breeding conditions. Numerous laboratory studies have revealed that light experienced during a critical window of the circadian (daily) rhythm can influence reproductive physiology. However, whether these relationships observed in captivity hold true under natural conditions and how they relate to observed variation in timing of reproductive output remains largely unexplored. Here we test the hypothesis that individual variation in daily timing recorded in nature (i.e. chronotype) is linked with variation in timing of breeding. To address this hypothesis and its generality across species, we recorded incubation behavior data to identify individual patterns in daily onset of activity for 2 temperate-breeding songbird species, the dark-eyed junco (Junco hyemalis aikeni) and the great tit (Parus major). We found that females who first departed from their nest earlier in the morning (earlier chronotype) also initiated nests earlier in the year. Date of data collection and ambient temperature had no effect, but stage of incubation influenced daily onset of activity in great tits. Our findings suggest a role for daily rhythms as one mechanism underlying the observed variation in seasonal timing of breeding.

show abstract

“…Nest attentiveness also increased during the breeding season, perhaps due to an increase in food availability. Females were also more attentive with the increasing age of embryos, probably because the temperature of embryos needs to be more tightly regulated as embryos develop (Cooper and Voss ). Clutch size also positively affected nest attentiveness, which could be related to female quality, i.e., higher‐quality females were able to lay more eggs and be more attentive.…”

Section: Discussionmentioning

confidence: 99%

“…The measurement day, average daily ambient temperature, and clutch size were included as covariates. Due to the bias that measuring incubation behavior at different embryo ages can introduce in the analyses (Cooper and Voss ), we also included this variable in the analysis as a covariate. Embryo age was calculated as the number of days between the laying of the last egg in a clutch and the measurement day.…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Do extended incubation recesses carry fitness costs in two cavity-nesting birds?

et al. 2017

View full text Add to dashboard Cite

Because extended incubation recesses, where incubating songbirds are away from nests for periods much longer than usual, occur infrequently, they have been treated as outliers in most previous studies and thus overlooked. However, egg temperatures can potentially fall below the physiological zero temperature during extended recesses, potentially affecting developing embryos. As such, evaluating extended recesses in an ecological context and identifying their possible fitness effects are important. With this aim, we used iButton data loggers to monitor the incubation behavior of female Blue Tits (Cyanistes caeruleus) and Great Tits (Parus major) during two breeding seasons in central Spain. We classified incubation recesses as extended if they were more than four times the mean recess duration for each species. Extended incubation recesses occurred more frequently in 2012 when females exhibited poorer body condition. Female Blue Tits had more extended incubation recesses than female Great Tits and, for both species, more extended recesses occurred at the beginning of the breeding season. Both nest attentiveness and average minimum nest temperature decreased when at least one extended recess occurred. Incubation periods averaged 4 d longer for nests where females had at least one extended recess, potentially increasing predation risk and resulting in lower‐quality nestlings. Overall, our results suggest that extended recesses may be more common among songbirds than previously thought and that, due to their effects on egg temperatures and attentiveness, they could impose fitness costs.

show abstract

Avian Incubation Patterns Reflect Temporal Changes in Developing Clutches

Cited by 66 publications

References 37 publications

Experimental reduction of haematocrit affects reproductive performance in European starlings

Experimental reduction of haematocrit affects reproductive performance in European starlings

Early to rise, early to breed: a role for daily rhythms in seasonal reproduction

Do extended incubation recesses carry fitness costs in two cavity-nesting birds?

Contact Info

Product

Resources

About