Eggshell coloration indicates female condition during egg-laying: a field experiment in blue tits

AbstractSeveral selection pressures may explain the evolution of avian eggshell coloration patterns. In cavity-nesting species, there are two main non-exclusive hypotheses. The sexually selected eggshell colour hypothesis proposes that eggshell coloration is a sexually selected signal of female and offspring quality used by males that influences paternal care or future re-mating decisions. The structural function hypothesis proposes that pigments help strengthen the eggshell and are present at higher levels and at the blunt end of the egg when females face calcium shortages. We tested whether eggshell coloration (brown spots on a white ground colour) in blue tits (Cyanistes caeruleus) could reliably indicate female condition at laying by forcing females to produce two consecutive clutches, thus increasing their reproductive costs. Three measures of eggshell coloration – the area covered by spots as well as white ground UV-chroma and brightness – changed between clutches; the fourth measure, spot distribution, did not. The changes were more dramatic in young and lower-quality females. All the measures varied with female quality (i.e. body condition and/or laying date). Overall, higher-quality females produced more colourful (larger, more concentrated spotted surface area; higher UV-chroma) and less bright (i.e. putatively more pigmented) eggshells, a result that is generally in line with past research. We found a clear empirical link between eggshell coloration and female condition in blue tits, an important step in determining whether eggshell coloration is a sexual signal, but which does not exclude a potential concomitant structural function.

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Effects of Food Abundance, Weather, and Female Condition on Reproduction in Tree Swallows (Tachycineta Bicolor)

The Auk ◽

10.1093/auk/122.4.1225 ◽

2005 ◽

Vol 122 (4) ◽

pp. 1225-1238 ◽

Cited By ~ 5

Author(s):

Jacqueline K. Nooker ◽

Peter O. Dunn ◽

Linda A. Whittingham

Keyword(s):

Body Condition ◽

Egg Laying ◽

Food Abundance ◽

Tachycineta Bicolor ◽

Laying Date ◽

Foraging Efficiency ◽

Tree Swallows ◽

Female Condition ◽

Incubation Periods ◽

Feather Clipping

AbstractFood abundance, weather, and female body condition are believed to influence the timing of breeding and reproductive performance of birds. We simultaneously studied the effects of weather and food abundance on reproduction in Tree Swallows (Tachycineta bicolor) while experimentally reducing female condition and foraging efficiency by clipping some flight feathers prior to egg laying. Control females laid larger clutches earlier in the season, had longer incubation periods, and raised heavier nestlings than experimental females. Fledging success did not differ after controlling for laying date and brood size. Greater insect abundance was associated with laying earlier in the season, heavier eggs, and shorter incubation periods. Most likely, feather-clipping affected clutch size through reduced foraging efficiency, which delayed the date of laying, rather than through loss of body condition. This outcome is consistent with the idea that Tree Swallows are “income” breeders that base their timing of reproduction on short-term rates of food intake near the time of breeding. Contrary to studies of other species, Tree Swallows do not appear to time their laying so that hatching will coincide with seasonal peaks in food supply. Rather, they appear to breed when temperature and food abundance are sufficient to allow females of a given body condition to initiate egg laying.Efectos de la Abundancia de Alimento, del Clima y de la Condición de las Hembras sobre la Reproducción en Tachycineta bicolor

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The environmental predictors of spatio-temporal variation in the breeding phenology of a passerine bird

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2019.0952 ◽

2019 ◽

Vol 286 (1908) ◽

pp. 20190952 ◽

Cited By ~ 2

Author(s):

Jack D. Shutt ◽

Irene Benedicto Cabello ◽

Katharine Keogan ◽

David I. Leech ◽

Jelmer M. Samplonius ◽

...

Keyword(s):

Passerine Bird ◽

Egg Laying ◽

Laying Date ◽

Reproductive Phenology ◽

Breeding Phenology ◽

Environmental Predictors ◽

Cyanistes Caeruleus ◽

Night Time ◽

Lay Date ◽

Nest Initiation

Establishing the cues or constraints that influence avian timing of breeding is the key to accurate prediction of future phenology. This study aims to identify the aspects of the environment that predict the timing of two measures of breeding phenology (nest initiation and egg laying date) in an insectivorous woodland passerine, the blue tit ( Cyanistes caeruleus ). We analyse data collected from a 220 km, 40-site transect over 3 years and consider spring temperatures, tree leafing phenology, invertebrate availability and photoperiod as predictors of breeding phenology. We find that mean night-time temperature in early spring is the strongest predictor of both nest initiation and lay date and suggest this finding is most consistent with temperature acting as a constraint on breeding activity. Birch budburst phenology significantly predicts lay date additionally to temperature, either as a direct cue or indirectly via a correlated variable. We use cross-validation to show that our model accurately predicts lay date in two further years and find that similar variables predict lay date well across the UK national nest record scheme. This work refines our understanding of the principal factors influencing the timing of tit reproductive phenology and suggests that temperature may have both a direct and indirect effect.

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Influence of fine-scale habitat structure on nest-site occupancy, laying date and clutch size in Blue Tits Cyanistes caeruleus

Acta Oecologica ◽

10.1016/j.actao.2015.11.006 ◽

2016 ◽

Vol 70 ◽

pp. 37-44 ◽

Cited By ~ 17

Author(s):

Seyed Mehdi Amininasab ◽

Oscar Vedder ◽

Elske Schut ◽

Berber de Jong ◽

Michael J.L. Magrath ◽

...

Keyword(s):

Clutch Size ◽

Habitat Structure ◽

Nest Site ◽

Site Occupancy ◽

Laying Date ◽

Fine Scale ◽

Cyanistes Caeruleus ◽

Blue Tits

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Selection on reproductive plasticity in a wild population of blue tits, Cyanistes caeruleus

10.32942/osf.io/crkdf ◽

2019 ◽

Author(s):

Heung Ying Janet Chik ◽

Catalina Estrada ◽

Yiqing Wang ◽

Priyesha Vijendra ◽

Alex Lord ◽

...

Keyword(s):

Clutch Size ◽

Wild Population ◽

Reaction Norm ◽

Reaction Norms ◽

Random Regression ◽

Laying Date ◽

Stabilizing Selection ◽

Chick Survival ◽

Cyanistes Caeruleus ◽

Blue Tits

In the plant-insect-insectivorous-bird system, changing climates can result in mis-timing in bird reproduction, potentially impacting chick survival. To adapt to earlier prey emergence, birds can make use of phenotypic plasticity, which can be characterized by reaction norms. Despite gaining focus in research, studies on avian reproductive reaction norms as traits are scarce, particularly on laying-date-budburst-date and clutch-size-laying-date reaction norms. Here we examined the possibility of evolution of these two reaction norms from a quantitative genetics viewpoint, and tested whether 1) there is among-individual variance in reaction norms properties (intercept and slope); 2) there is selection on these reaction norm properties; and 3) variances and selection pressures differ between the two reaction norms. Data of oak (genus Quercus) budburst and blue tit (Cyanistes caeruleus) reproduction were collected from a wild population for 18 years. We used bivariate random regression models with a Bayesian approach to test for among-individual variance in reaction norm properties and their covariance with fitness. Individuals significantly differed in intercepts and slopes of both laying-date-budburst-date and clutch-size-laying-date reaction norms, and directional selection was present for an earlier laying date and a larger clutch size, but not on either plasticity. Results suggested that variation in reaction norm properties can be attributed to genetic and environmental effects, and that stabilizing selection on plasticity could be tested as a next step. This study compliments previous research on the evolution of reaction norms and helps shed light on their genetic structure, the context of their selection, and their mediation in birds.

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A Blue Tit Cyanistes caeruleus population: its recent increase and breeding data

Ornis Svecica ◽

10.34080/os.v21.22597 ◽

2012 ◽

Vol 22 (1–2) ◽

pp. 19-24

Author(s):

Karl Gustav Schölin ◽

Hans Källander

Keyword(s):

Population Size ◽

Negative Relationship ◽

Breeding Population ◽

Laying Date ◽

Strongly Correlated ◽

Blue Tit ◽

Cyanistes Caeruleus ◽

South Central ◽

The Mean ◽

Blue Tits

Before 1983, Blue Tits Cyanistes caeruleus never made up more than four pairs of the breeding population in a nestbox study carried out in South Central Sweden. From five breeding pairs in 1983, the population increased to 29 pairs in 2007 and remained high to the end of the study in 2011. Mean laying date was strongly correlated with mean April temperature, which increased during 1983–2011. During the same period mean laying date became nearly ten days earlier. Mean clutch size was 9.90 eggs but varied both within and between years and showed a negative relationship to population size. The mean number of fledglings varied strongly between years, partly because of predation but also due to nestling starvation.

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Between-population differences in egg composition in Blue Tits (Cyanistes caeruleus)

Canadian Journal of Zoology ◽

10.1139/z06-189 ◽

2007 ◽

Vol 85 (1) ◽

pp. 71-80 ◽

Cited By ~ 18

Author(s):

Patrice Bourgault ◽

Donald W. Thomas ◽

Jacques Blondel ◽

Philippe Perret ◽

Marcel M. Lambrechts

Keyword(s):

Fatty Acids ◽

Clutch Size ◽

Food Availability ◽

Egg Laying ◽

Population Differences ◽

Cyanistes Caeruleus ◽

Shell Mass ◽

Habitat Differences ◽

Egg Composition ◽

Blue Tits

Egg production may be influenced by environmental conditions such as local climate or food availability, which may impose physiological constraints on the acquisition and mobilization of egg constituents. We analyzed egg composition of free-ranging female Blue Tits ( Cyanistes caeruleus (L., 1758)) in both deciduous and evergreen oak habitats, which showed large differences in temperature and food availability. We found marked interhabitat differences in yolk mass, shell mass, protein content, and the abundance of linolenic (18:3) and palmitoleic (16:1) fatty acids. A weak but significant decline in total lipid content, as well as 14:0, 16:0, and 18:0 fatty acids, through the laying sequence was also detected. To our knowledge, this is the first evidence of between-population differences in nutrient allocation in eggs for a wild passerine. These differences in egg composition could be viewed as evidence of habitat-specific physiological and nutritional constraints, which in turn may contribute to the contrasting differences in timing of breeding and clutch size that we observed between both habitats. Our results point out the importance of habitat differences in our understanding of the causes and consequences of interhabitat phenotypic variation in breeding traits (timing of egg laying, clutch size) and variation in nestling traits such as growth and development.

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Experimental increase in female mass during the fertile phase leads to enhanced extra-pair paternity in pied flycatchers Ficedula hypoleuca

10.32942/osf.io/qrnkb ◽

2019 ◽

Author(s):

Mireia Plaza ◽

Alejandro Cantarero ◽

Juan Moreno

Keyword(s):

Negative Relationship ◽

Ficedula Hypoleuca ◽

Egg Laying ◽

Female Dominance ◽

Laying Date ◽

Control Group ◽

Wing Loading ◽

Potential Fecundity ◽

Fertile Phase ◽

Extra Pair Paternity

Female mass in most altricial birds reaches its maximum during breeding at egg-laying, which coincides temporally with the fertile phase when extra-pair paternity (EPP) is determined. Higher mass at laying may have two different effects on EPP intensity. On the one hand, it would lead to increased wing loading (body mass/wing area), which may impair flight efficiency and thereby reduce female’s capacity to resist unwanted extra-pair male approaches (sexual conflict hypothesis). On the other hand, it would enhance female condition, favouring her capacity to evade mate-guarding and to search for extra-pair mates (female choice hypothesis). In both cases, higher female mass at laying may lead to enhanced EPP. To test this prediction, we reduced nest building effort by adding a completely constructed nest in an experimental group of female pied flycatchers (Ficedula hypoleuca). Our treatment caused an increase in mass and thereby wing loading and this was translated into a significantly higher EPP in the manipulated group compared with the control group as expected. There was also a significant negative relationship between EPP and laying date and the extent of the white wing patch, an index of female dominance. More body reserves at laying mean not only a higher potential fecundity but a higher level of EPP as well. This interaction had not previously received due attention but should be considered in future studies of avian breeding strategies.

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