Surface temperatures of albatross eggs and nests

Philipp H Boersch-Supan,Leah R Johnson,Richard A Phillips,Sadie J Ryan

doi:10.1080/01584197.2017.1406311

Abstract

ABSTRACTKnowledge of thermal traits is essential for understanding and modelling physiological responses to environmental change. Egg temperatures are poorly studied in most tubenose species. We employed a contactless infrared thermometer to measure egg and nest surface temperatures throughout the incubation period for four albatross species at Bird Island, South Georgia. The observed mean warm-side temperature of 33.4°C for Wandering Albatross (Diomedea exulans) was similar to measurements obtained from this species using dummy eggs elsewhere. Observed mean warm-side temperatures for Black-browed Albatross (Thalassarche melanophris), Grey-headed Albatross (Thalassarche chrysostoma), and Light-mantled Albatross (Phoebetria palpebrata), reported here for the first time, were 30.7–31.5°C, which is lower than the egg temperatures reported for most Procellariiformes. Temperature gradients across viable eggs declined by up to 9°C during incubation, reflecting increased embryonic circulation and metabolic heat production. This suggests that bioenergetic models should not assume constant egg temperatures during embryo development. Non-viable (addled) eggs could be identified by large temperature gradients in late incubation, indicating that infrared thermometry can be used to determine whether the embryo has died or the egg is infertile in monitoring and managed breeding (e.g. translocation) programmes. Egg temperatures were correlated with ground temperatures, indicating that incubated eggs are vulnerable to environmental variability.

Highlights

Avian incubation is inextricably linked to temperature, and sensitive to a changing climate (Mainwaring 2015)
Quantifying thermal traits is an essential precursor for better understanding and modelling seabird physiological responses to a changing environment (Konarzewski et al 1998; Teixeira et al 2014)
No temporal trends related to incubation duration were observed in warmside temperatures (LMM, β = 0.00, 95% CI −0.02–0.02) after accounting for the variation in ground temperatures (Table S2), but cold-side temperatures increased during incubation by 0.11°C per day, resulting in a decreasing across-egg temperature gradient (Figure 1)

Summary

Introduction

Avian incubation is inextricably linked to temperature, and sensitive to a changing climate (Mainwaring 2015). Changing environmental conditions have the potential to shape many aspects of avian biology, including through direct physiological impacts (Oswald and Arnold 2012). Our understanding of seabird responses to direct impacts of global warming is incomplete (Grémillet et al 2012). Quantifying thermal traits is an essential precursor for better understanding and modelling seabird physiological responses to a changing environment (Konarzewski et al 1998; Teixeira et al 2014). The incubated egg is a complex living system, and incubation is a thermal mutualism, mediated by the physiology of both parent and embryo, and heat exchanges with the environment; as a result, different parts of the eggs can be at very different temperatures (Turner 2002)

Methods

Results

Conclusion