Heart-rates of European bee-eaters migrating over southern Israel

Meeting Abstract

60.9  Tuesday, Jan. 6  Heart-rates of European bee-eaters migrating over southern Israel SAPIR, N.*; NATHAN, R.; WIKELSKI, M.; The Hebrew University of Jerusalem; The Hebrew University of Jerusalem; Max Planck Institute for Ornithology nir.sapir@mail.huji.ac.il

One of the major challenges in the study of long-distance bird migration is the quantification of bird behavior and energetics during both stopover and cross-country flight periods. Progress in addressing this challenge is still hampered by scarcity of tools for simultaneously acquiring bird location and energetics en route. During the springs of 2005 and 2006 we trapped eleven 50 g European bee-eaters (Merops apiaster) migrating over southern Israel and attached them with a 1-g continuously-emitting transmitter that was frequency modulated by heart and flight muscle potentials. The birds stayed in the area for 0.5 to 9 days before departing during daytime for cross-country flights of up to 220 km, during which their heart-beat and wing-flap rates were recorded by two vehicle-mounted telemetry systems. Bird behavior during tracking was documented by direct observations and was corroborated by the wing-flap signal, the null-reception pattern and telemetry bird movement measurements. We found that wing-flap rate was significantly lower during stopover flights comprised of continuous flaps compared with cross-country flap-pause flights. Heart-beat rate during stopover powered flights was 10 % higher but statistically indistinguishable from powered cross-country flights, and was 2.6 times higher than resting heart-beat rate. Heart-beat rate during resting was statistically indistinguishable from both stopover and cross-country soaring flights. Our results suggest that, as expected, powered flight is much more energetically demanding than soaring flight. Surprisingly, soaring flight in this species seem to be associated with particularly low heart-beat rate compared with other, much larger, soaring bird species.

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