Biography:

In the past D.J. McCafferty has collaborated on articles with W. Paterson. One of their most recent publications is Seals like it hot: Changes in surface temperature of harbour seals (Phoca vitulina) from late pregnancy to moult. Which was published in journal Journal of Thermal Biology.

More information about D.J. McCafferty research including statistics on their citations can be found on their Copernicus Academic profile page.

D.J. McCafferty's Articles: (3)

Seals like it hot: Changes in surface temperature of harbour seals (Phoca vitulina) from late pregnancy to moult

AbstractThe annual moult in harbour seals (Phoca vitulina L.) follows a few weeks after the end of lactation and is characterised by a progressive loss and regrowth of hair which is apparent over a 4–6 week period. It is thought that during the moult harbour seals increase the time spent ashore as an adaptation to avoid additional energy costs associated with blood flow to the skin surface. The aim of this study was to determine the extent to which harbour seals regulated their surface temperature in order to maximise hair regrowth during the moult. The surface temperatures of two female harbour seals were recorded in captivity from late pregnancy to completion of the moult using infrared thermography. In this study, animals hauled out (exited the water onto land) more frequently during lactation and throughout the moult. Compared to the premoult period the temperature difference between body surface and air temperature (dT¯) showed a ∼10 °C elevation at the peak of the moult. Also, during the moult dT¯ reached a higher maximum at a faster rate over a two hour haul-out period. Heat loss was estimated to increase during the moult and was equivalent to an approximate doubling of resting metabolic rate. It was therefore evident that harbour seals minimise the energetic cost of the moult by hauling out so that they can maintain optimal high skin surface temperature for hair growth. Human disturbance at haul-out sites that causes animals to enter the water during the moult may have consequences for harbour seals for two reasons. Firstly, reduced time spent ashore in optimal conditions for hair regeneration may prolong the duration of the moult and secondly, repeatedly forcing animals into the water when their skin temperature is high will incur an energetic cost.

The effect of wind speed and wetting on thermal resistance of the barn owl (Tyto alba). II: Coat resistance

Abstract1.1. The thermal resistance of barn owl (Tyto alba) plumage was determined from measurements of heat flux and temperature using a model in a wind tunnel.2.2. The mean resistance of four barn owl coats was 398 s m−1 and wetting the coat reduced coat resistance to 374 s m−1. Resistance decreased linearly with increasing wind speed from 0–7 m s−1.3.3. Half of the heat transfer within barn owl coats occurred by conduction through the feather elements, the remaining heat transfer was due to molecular diffusion of air within the coat (30%), radiation (10%) and free convection (10%).4.4. Thermal properties of barn owl plumage were comparable with previous findings on avian coats.

The use of IR thermography to measure the radiative temperature and heat loss of a barn owl (Tyto alba)

AbstractInfrared (IR) thermography was used to identify the major sites of heat loss from a female barn owl at an air temperature of 17.6°C. When perched, the mean radiative temperature of the owl was 21.1°C (SD=3.5). The facial disc averaged 23.9°C (SD=9.1) and the temperature of the eyes was greater than 33°C. Images showed an area on the lower abdomen that was warmer than 27°C. During flight, the temperature of plumage overlying wing muscles was more than 30°C.The metabolic heat production of the barn owl was estimated to be 42 W m−2 (1.68 W) at 17.6°C which agreed with previous measurements of metabolism. Heat loss from the head was almost double that from the body as a whole, indicating the importance of reducing exposure of the head during roosting.The metabolic rate during flight was calculated to be 13×BMR (Pennycuick, 1989). This suggested that barn owls lose considerable amounts of heat during prolonged periods of flight. It is hypothesised that by being active in cool nocturnal conditions, barn owls may exploit waste metabolic heat for thermoregulation.

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