Evaluation of Radio Transmitters for Measuring Chick Mortality in the Banded Dotterel

Abstract

-Radio transmitters have potential for measuring rates and causes of mortality in precocial chicks. To assess their utility, elastic harnesses were used to attach radio transmitters to 49 newly hatched Banded Dotterel (Charadrius bicinctus) chicks, a bird breeding along braided rivers of the South Island, New Zealand. Twelve chicks either lost their transmitters or the transmitters were removed, six chicks survived to fledging, 26 chicks died and the outcome was unclear for the remaining five chicks. A minimum of 18% of chicks that died were taken by predators, but predator identity was clear in only one case. The transmitters did not appear to affect growth rates of radiomarked chicks, but three chicks died from harness entanglement. This technique provided only limited information about causes of mortality in Banded Dotterel chicks, and radio transmitters attached with elastic harnesses are not suitable for young chicks. Received 2 March 2001, accepted 20 April 2001.