Renesting by American Woodcocks (Scolopax minor) in Maine

The American Woodcock (Scolopax minor) is one of the earliest ground-nesting birds in the northeastern United States. In Maine, nesting begins in early April when temperatures can drop below freezing and significant snowfall can accumulate. Nests are usually in open woods, where eggs are laid on the ground in a shallow depression (Pettingill 1936, Mendall and Aldous 1943, Sheldon 1967). Peak hatching occurs in early May (Dwyer et al. 1982), when temperatures are cool and precipitation is common. Woodcock chicks are dependent on the female for most of their food for at least seven days after hatching (Gregg 1984). During cool, wet weather, chicks require constant brooding by females; prolonged periods of inclement weather may lead to substantial mortality of chicks (Dwyer et al. 1988). This reproductive strategy led Pettingill (1936), Mendall and Aldous (1943), and Sheldon (1967) to speculate that renesting by American Woodcock is common, although they could not document this behavior. Renesting would seem necessary to maintain adequate recruitment because American Woodcock clutches are small (3-4 eggs), nest success is 50-67% (Mendall and Aldous 1943, Gregg 1984), and chick survival is 59% (Dwyer et al. 1988). Renesting after loss of a clutch has been documented for other shorebirds, including the Eurasian Woodcock (Scolopax rusticola; Hirons and Owen 1982), plovers (Charadrius spp.; Warriner et al. 1986), Spotted Sandpipers (Actitis macularia; Lank et al. 1985, Oring and Lank 1986), Killdeer (Charadrius vociferus; Brunton 1988), and Rednecked Phalaropes (Phalaropus lobatus; Reynolds 1987). Some shorebird species are polyandrous (Schamel and Tracy 1977, Lank et al. 1985, Oring 1985, Reynolds 1987), and a few species are double-brooded (Brunton 1988). Only circumstantial evidence of late-nesting birds (Ammann 1967, Parris 1983) and prolonged brood seasons (Rabe 1979) suggest that woodcocks will renest. We present the first definitive records of renesting by American Woodcocks during a single nesting season. We conducted this study on the 6,850-ha Baring unit of Moosehorn National Wildlife Refuge (NWR) near Calais, Maine, on the New Brunswick border. Dwyer et al. (1988) described the study area in detail. Female woodcocks were captured in mist nets on courting areas. Females on nests and those with broods were located by a pointing dog and captured with hand nets (Ammann 1977). All nesting females and females with broods '5 days old were radio-marked. Females were aged by wing-plumage characteristics (Martin 1964) and classified as 1 year old (SY) or -2 years old (ASY). We weighed each bird at the time of capture and attached a 3.5-4 g transmitter to its back by livestock-tag cement and a single-loop wire harness (Derleth 1986). We located birds daily from vehicles or on foot with portable receivers and handheld antennas. Lost birds were located from light, fixed-wing aircraft with antennas attached to the struts (Gilmer et al. 1981). We flew transects 3.2 km apart across the study area and ? 16 km beyond its borders. Transmitter signals were detectable ?0.8 km from the ground and 20 days of age. Her reproductive tract contained