Metabolic response to wind of downy chicks of Arctic-breeding shorebirds

• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2002
• Subjects: water loss; down; least sandpiper; Calidris minutilla; short-billed; Arctic; Numenius phaeopus; Tundra; Whimbrel
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.408.7232; http://www.biosci.ohio-state.edu/~patches/publication/Bakken et al_2002_shorebirds.pdf

Wind is a significant factor in the thermoregulation of chicks of shorebirds on the Arctic tundra. We investigated the effect of wind at speeds typical of near-surface conditions (0.1–3 m s –1) on metabolic heat production, evaporative cooling and thermal conductance of 1- to 3-week-old downy scolopacid chicks (least sandpiper Calidris minutilla; short-billed dowitcher Limnodromus griseus; whimbrel Numenius phaeopus). Body mass ranged from 9 to 109 g. To accurately measure the interacting effects of air temperature and wind speed, we used two or more air temperatures between 15 ° and 30°C that produced cold stress at all wind speeds, but allowed chicks to maintain normal body temperature (approximately 39°C). Thermal conductance increased by 30–50 % as wind speed increased from 0.1 to 3 m s –1. Conductance in Summary these chicks is somewhat lower than that of 1-day-old mallard ducklings of similar mass, but higher than values reported for downy capercaillie and Xantus ’ murrelet chicks, as well as for adult shorebirds. Evaporative water loss was substantial and increased with mass and air temperature. We developed a standard operative temperature scale for shorebird chicks. The ratio of evaporative cooling to heat production varied with wind speed and air temperature.