Capturing wild birds with mist nets is very common for studying many aspects of avian biology. However, except for adrenocortical reactivity, little is known about other physiological responses to this potentially stressful procedure. Here, we focused on body temperature (Tb) in migratory songbirds, as large numbers are caught for population monitoring and studies of migratory biology. Tb is sensitive to acute stress in other vertebrates and contexts, usually showing an increase (stress-induced hyperthermia). We sampled garden warblers (Sylvia borin), whinchats (Saxicola rubetra) and barn swallows (Hirundo rustica) captured with mist nests using standard protocols at an island stopover site in the central Mediterranean during spring migration. Tb was measured within 3 min (T0), 30 min (T30) and 180 min (T180) from the time the bird hit the net, using an analogue probe inserted into the throat, and a body condition score was calculated for each bird. In the garden warbler, but not the other two species, a slight but significant reduction in Tb occurred after 180 min. In all species, the change in Tb after 3 h of confinement was positively correlated to the change in ambient temperature (Ta) but not to body condition. The mean (± SEM) change in Tb over 3 h was −1.68 (± 0.16)°C for garden warblers, therefore within the expected range of normothermy in small birds. Such reduction in Tb is contrary to the expectation of stress-induced hyperthermia; these results suggest that garden warblers are able to modulate their body temperature and that these small changes are influenced by fluctuations in ambient temperature. Therefore, Tb might not be a good indicator of capture stress in small passerine migrants. Our results also indicate that restraint for ringing procedures is unlikely to have adverse effects on Tb regulation of migratory birds, if held within the time-frame typical of ringing operations.

Daily heterothermy is a strategy employed by endothermic birds and mammals to reduce their energetic costs by lowering their metabolic rate. We recorded nocturnal and diurnal rectal temperatures in three Moroccan Gerbillus rodent species to determine the level of heterothermy. A decrease in body temperature from night to day was observed by an average (±SD) of 8.7 (±4.2) in G. gerbillus, 11.1 (±3.0) in G. amoenus, and 7.7 (±3.3)°C in G. sp.1, the first records of heterothermy in the three species. The findings support a prediction that daily heterothermy is found in mammals from arid and semi-arid regions, contributing to further knowledge of thermoregulation in desert rodents.

Necrophagous flies that colonize human and animal corpses are extremely efficient at locating and utilizing carrion. Adult flies deposit eggs or larvae on the ephemeral food resource, which signals the beginning of intense inter- and intra-species competition. Within a short period of time after egg hatch, large larval aggregations or maggot masses form. A period of intense larval feeding ensues that will culminate with consumption/decomposition of all soft tissues associated with the corpse. Perhaps the most distinctive feature of these feeding aggregations is heat production; that is, the capacity to generate internal heat that can exceed ambient temperatures by 30°C or more. While observations of maggot mass formation and heat generation have been described in the research literature for more than 50 years, our understanding of maggot masses, particularly the physiological ecology of the aggregations as a whole, is rudimentary. In this review, an examination of what is known about the formation of maggot masses is presented, as well as arguments for the physiological benefits and limitations of developing in feeding aggregations that, at times, can represent regions of intense competition, overcrowded conditions, or a microclimate with elevated temperatures approaching or exceeding proteotoxic stress levels.

In highly seasonal environments animals that use daily torpor usually do so during the rest phase. In subtropical and tropical environments, however, daily torpor may not necessarily be confined to the animals' rest phase. Animals may display torpor during the active phase. We investigated the daily rhythms and seasonal rhythms of body temperature (Tb) in normothermic and torpid free-ranging rock elephant shrews Elephantulus myurus at Weenen Game Reserve, KwaZulu-Natal, South Africa. Tbs were recorded using miniature dataloggers from May 2001 to May 2002. Daily patterns of Tb in normothermic E. myurus suggested polyphasic Tb patterns that nevertheless suggested a rest phase that was coincident with the daytime. When the elephant shrews used torpor, the lowest Tbs were observed during the night-time, such that torpor was used during the coldest part of the night and arousal was associated with the 3-h period around sunrise. We suggest that the principal benefit of a flexible daily rhythm of Tb was that it facilitated arousal by passive exogenous heating using ambient temperature cycles.