Effects of Environmental Conditions and Parental Quality on Inter- and Intraclutch Egg-Size Variation in the Collared Flycatcher (Ficedula Albicollis)

Abstract

Egg size is a particularly important life-history trait mediating maternal influences on offspring phenotype. Females can vary their egg-size investment in relation to environmental circumstances, their own breeding condition, and the quality of their mate. Here we analyzed inter- and intraclutch variation in egg size in the Collared Flycatcher (Ficedula albicollis) on the basis of eight years of data. According to our results, mean egg size increased with female condition, but did not differ among young, middle-aged, and old females. The male’s age, body size, and forehead patch size did not influence egg size; thus, we found no evidence for differential investment in egg size in relation to male quality. We found no effect of laying date on egg size when controlling for ambient temperature during the egg formation period, yet temperature had a significant effect on egg size. That result indicates proximate constraints on egg formation. Furthermore, we report on annual differences in intraclutch egg-size variation. Egg size increased within clutches in years with a warm prelaying period; whereas in years when the weather during that period was cold, there was no significant intraclutch trend. Proximate considerations seem to explain the observed patterns of intraclutch egg-size variation; however, we cannot reject the adaptive explanation. Mean egg size and intraclutch egg-size variation were unrelated to clutch size. Therefore, we found no evidence for a trade-off between size and number of eggs within a clutch.

Eggshell coloration in relation to male ornamentation, female condition and egg quality in the collared flycatcherFicedula albicollis

“…As the adaptive explanation suggests, females may enhance resource allocation with laying order so as to facilitate survival of later-hatching nestlings (''brood-survival strategy'', Slagsvold et al 1984). In concert with this hypothesis, within-clutch increase in egg size (Hargitai et al 2005), yolk beta-carotene ) and immunoglobulin concentrations (Hargitai et al 2006a) were found in this species. Thus, it is possible that the within-clutch increase in the intensity of egg colour is the result of a link between the deposition of biliverdin pigment and some other component (e.g.…”

Maternal immunoglobulin concentration in Collared Flycatcher (Ficedula albicollis) eggs in relation to parental quality and laying order

“…In the Collared Flycatcher, however, previous studies have shown that the concentration of β-carotene (J. Török, R. Hargitai, G. Hegyi, Z. Matus, G. Michl, P. Péczely, B. Rosivall, & Gy. Tóth, unpublished data) and egg volume (Cichon 1997;Hargitai et al 2005;Rosivall et al 2005) increase along the laying sequence within a clutch, providing support for the idea that Collared Flycatchers pursue a 'brood-survival' strategy.…”

The trade‐off between clutch size and egg mass in tree swallowsTachycineta bicoloris modulated by female body mass

“…Since body mass explains over 50% of the variation in bird fat reserves (Labocha and Hayes 2011), it is likely that these reserves allow heavier females to produce larger eggs. Additionally, heavier females may be able to produce larger eggs while conserving sufficient resources for parental care, while it may not be possible for lighter females (Hargitai et al 2005). Females nesting in agriculturally intensive landscapes laid fewer eggs per clutch on average than females from areas dominated by extensive cultures (i.e.…”