Effects of male removal on female reproductive biology in Ross' and Lesser Snow Geese

Abstract

We studied effects of mate removal on nesting and hatching success, incubation behavior, body mass, and post-hatch dispersal distance of female Ross' (Chen rossii) and Lesser Snow Geese (C. caerulescens caerulescens) at Karrak Lake. N.W.T., Canada. Male ge and widowed and paired control females were monitored through post-hatch dispersal. Nesting and hatching success did not differ between species or treatments (widowed vs paired) and averaged 77.5 ?? 3.8% and 64.0 ?? 3.6% (??SE), respectively. Paired females spent more time with their bills tucked (23.7 ?? 3.3% vs 9.1 ?? 4.0%) and less time alert (8.6 ?? 2.9% vs 22.9 ?? 3.5%) while on nests than did widowed females. Snow widowed females (31.1 ?? 4.7%) and Ross' widowed females (20.6 ?? 6.0%) generally spent more time each day in head-up alert than did Snow paired females (7.1 ?? 3.8%). Snow paired maleS (11.8 ?? 3.8%), Ross' paired females (9.4 ?? 3.6%), and Ross' paired males (7.9 ?? 3.6%). Body mass of paired and widowed female Ross' Geese did not differ at hatch or at time of post-hatch recapture; however, mean distance recaptured from the breeding colony was greater for paired (50.9 ?? 6.1 km) than for widowed females (27.3 ?? 6.6 km). Total mass gain (276 ?? 19 g) and rate of mass gain (8.4 ?? 0.5 g/day), from hatch until post-hatch recapture (33.1 ?? 1.2 days), were similar for widowed and paired female Ross' Geese. Male removal experiments in monogamous, precocial species generally have produced few effects on female nesting success or incubation behavior. We suggest that male parental care in arctic-nesting geese is more critical during laying and the post-hatch period than during incubation.