Experimentally increased nest temperature affects body temperature, growth and apparent survival in blue tit nestlings

Abstract

The thermal environment experienced by birds during early postembryonic development may be an important factor shaping growth and survival. However, few studies have directly manipulated nest temperature (T n) during the nestling phase, and none have measured the consequences of experimental heat stress on nestlings’ body temperature (T b). It is therefore not known to what extent any fitness consequences of development in a thermally challenging environment arise as a direct, or indirect, effect of heat stress. We, therefore, studied how experimentally increased T n affected T b in 8–12 d old blue tit Cyanistes caeruleus nestlings, to investigate if increased thermoregulatory demands to maintain normothermic T b influenced nestling growth and apparent long‐term survival. Nestlings in heated nest‐boxes had significantly higher T b compared to unheated nestlings during most of the experimental period. Yet, despite facing T n  50°C (as measured in the bottom of the nest cup below the nestlings), the highest nestling T b recorded was 43.8°C with nestlings showing evidence of controlled facultative hyperthermia without any increased nestling mortality in heated nests. However, body mass gain was lower in these nestlings compared to nestlings from control nest‐boxes. Contrary to our prediction, a larger proportion of nestlings from heated nest‐boxes were recaptured during their first winter, or subsequently recruited into the breeding population as first‐ or second‐year breeders. This result should, however, be treated with caution because of low recapture rates. This study highlights the importance of the thermal environment during nestling development, and its role in shaping both growth patterns and possibly also apparent survival.

Temperature and breeding success for Cliff Swallows (Petrochelidon pyrrhonota) nesting on man-made structures: ecological traps?

“…These effects are particularly severe for cliff swallows nesting under eaves with metal roofs, as higher ambient temperatures result in even higher eave temperatures when compared to eaves under wood roofs. These findings are consistent with D r a f t other research demonstrating that high nest temperatures have detrimental effects on nestling survival and body condition (Erbelding-Denk and Trillmich 1990;Lombardo 1994;Greño et al 2008;Cunningham et al 2013;Larson et al 2015;Rodríguez and Barba 2016), and that some nestlings may have limited options for mitigating the effects of high temperatures (Fairhurst et al 2012; but see Andreasson et al 2018).…”

Testing for context-dependent effects of maternal thyroid hormones on offspring survival and physiology: an experimental approach manipulating temperature in a wild bird species

“…(ii) Our experimental temperature manipulation was rather small, which could have either been compensated by maternal brooding (though brooding did not seem to differ among the groups) or simply too small to induce measurable changes in growth. In previous studies, ca 5 ºC elevation led to a decrease in body mass in blue tits (Cyanistes caeruleus, 33) and great tits (Parus major, 41,42) and an increase in body mass in tree swallows (Tachycineta bicolor, 43); (iii) If maternal hormone transfer varies according to environmental context, our egg injection treatment might have resulted in different doses depending on the initial yolk hormone levels.…”

Analysis of random non-autonomous logistic-type differential equations via the Karhunen–Loève expansion and the Random Variable Transformation technique

“…The prominent role of the logistic differential equation to model problems in different settings as Biology (the dynamics of a population), Economics (the diffusion of a new technology or the growth of an economy), Engineering (the variation of physical properties subject to industrial processes), etc., has been extensively discussed and exhibited in numerous contributions (see for instance [1,2,3], [4,5] and [6,7], respectively). The logistic differential equation was first proposed by Pierre-François Verhulst, in his celebrated papers [8,9], to overcome the shortcomings of Malthusian's model to study the population growth.…”