Fat reserves and migration of Red-necked Phalaropes (Phalaropus lobatus) in the Quoddy region, New Brunswick, Canada

Abstract

Arrival, length of stay, fat deposition, flight range, and migration strategy of Red-necked Phalaropes (Phalaropus lobatus) were studied during the 1981–1982 autumn migrations through the Quoddy region, New Brunswick, Canada. Arrivals at this staging ground reflected the sequence in departures from the Arctic breeding grounds reported in the literature. Females arrived first, followed by males and finally juveniles, based on overall population composition during the season and patterns of fat deposition. Fat was deposited at the rate of 1.0 g per day over a period of about 20 days and maximum fat reserves amounted to between 40 and 45% of fresh weight, yielding enough for potential flight ranges of 4300–5100 km. The probable wintering grounds for the Quoddy region population are the waters off Peru, with the most direct migration route from the Bay of Fundy being some 6000 km long. This distance considerably exceeds the calculated nonstop flight capacities of Red-necked Phalaropes, and precludes their arriving at the wintering grounds without making another feeding stop, possibly off Panama.