The Effect of Wind on the Rate of Heat Loss from Avian Cup-Shaped Nests

Abstract

Forced convection can significantly influence the heat loss from birds and their offspring but effects may be reduced by using sheltered micro-sites such as cavities or constructing nests. The structural and thermal properties of the nests of two species, the spiny-cheeked honeyeater ( Acanthagenys rufogularis ) and yellow-throated miner ( Manorina flavigula ), were measured in relation to three wind speeds. Nest dimensions differ between the two species, despite the similar body mass of the incubating adults, however nest conductance is comparable. As wind speed increases, so does the rate of heat loss from the nests of both species, and further still during incubation recesses. The significance of forced convection through the nest is a near-doubling in heat production required by the parent, even when incubating at relatively low wind speeds. This provides confirmation that selecting a sheltered nest site is important for avian reproductive success.

Effects of Female Body Size and Phylogeny on Avian Nest Dimensions

“…This was because smaller birds (typically passerines) tended to produce disproportionately wider and deeper nests with relatively thicker walls than the non-passerines. By contrast, cup dimensions describe the space occupied by the bird and eggs and can be unrelated to other nest dimensions (Crossman et al, 2011;Heenan and Seymour, 2012). In the present study, cup diameter was highly correlated with body mass and exhibited no effect of taxon such that larger birds have relatively narrower nest cup diameters than smaller birds.…”

Morphology and biomechanics of the nests of the Common BlackbirdTurdus merula

“…Nests were stored for at least a year at approximately room temperature and humidity before analysis. Detailed observations of the arrangement of elements within the nest and identification of key structural regions were based upon observations and previous studies (Heenan & Seymour 2012, Mainwaring et al 2014. Nests were conditioned prior to testing at 23°C, 50% RH for 2 weeks in an environmental chamber (Sanyo MLR-351H, Osaka, Japan).…”

The design and function of birds' nests

“…Nest dimensions differ between the species, despite the adults having similar body masses, although the nest conductance of both species nests is comparable. The study found that the rate of heat loss from nests increased in both species as wind speed increased and as a result of forced convection through the nest, incubating parents would be required to double their heat production to maintain a suitable microclimate within the nest (Heenan and Seymour 2012). Nestbox-breeding prothonotary warbler ( Protonotaria citrea ) pairs that nested early in the season, when ambient temperatures were low, preferentially selected those nestboxes which had the highest ambient temperatures.…”