CAPTURING WHOOPING CRANES AND SANDHILL CRANES BY NIGHT-LIGHTING

Abstract

We caught 19 adult (> 1.5 years old) whooping craoes (Grus americana) in 84 capture attempts (23 % success) by nightlighting during 1981-91 in Idaho, Wyoming, and New Mexico, including 17 for experimental purposes and 2 that were debilitated (aviao cholera aod lead poisoning). We also captured 250 greater saodhill craoes (G. canadensis tabida), including 157 adults aod 93 juveniles, on summer areas at Grays Lake National Wildlife Refuge, Idaho, to color-mark them for behavioral and movement studies. Night-lighting equipment included an 8.5-kg portable generator mounted on an aluminum back-pack frame and a 12- or 28-V spotlight mounted on a helmet. Large fish laoding nets with 3.0- to 3.6-m haodles were used to capture craoes. Capture success was influenced by the presence of other avian species, habitat type, weather, and nocturnal conditions such as moon phase and amount of starlight. Cranes were most easily caught when roosting with few other cranes and other aquatic birds on very dark, overcast nights or during inclement weather. Night-lighting was a safe, effective, but strenuous technique for capturing cranes widely dispersed on summer areas and for targeting specific individuals. Fifty-three other avian species were captured with the back-pack night-lighting unit.