Nature Of Migration In The Species
Complete medium-distance migrant. Not known to overwinter on breeding lakes. Moves to freshwater breeding ponds in summer; otherwise marine. Subadults remain at sea throughout year. Rare in summer in most wintering areas. British birds banded as chicks migrate farther south the first winter than in subsequent years, and a higher percentage return to natal locales with each passing year. This is the only loon species with a complete remigial molt in the fall.
Timing And Routes Of Migration
Generally March through June; latitude-dependent, may continue over 4 months. Along East Coast, migration peaks in March in Virginia, April in Massachusetts; usually late April in inland Ontario. Peaks in Bay of Fundy near New Brunswick in early May; small flocks evident along s. British Columbia coast by late May; single birds begin to move north by early April; main movement late April-early May; individuals occasionally linger along northern coast to mid-June.
Arrival on summer range variable. In southern part of North American breeding range (Queen Charlotte Is., British Columbia), arrives 11-19 April. First sightings 5 and 11 June on North Slope of Alaska; for se. Beaufort Sea concentrations from Herschel Island to Cape Dalhousie, peak varies year to year, late May-mid-June. Pairs in northern part of range arrive after mid-June (Devon Island; Bathurst Island; nonbreeders continue to arrive until July; early arrivals 3 June on Baffin I. and Melville Peninsula. Territorial occupation in Arctic within 1 day of meltwater; until then, pairs remain on nearby ocean leads for up to 2 weeks (Alaska).
European populations migrate earlier. In Shetland Is., United Kingdom, pairs occupy territories as early as March and April (Okill 1994), may stay on lakes in groups of about15 up to 2 months until onset of breeding; 29 June is earliest arrival reported from Severnaya Zemlya, Siberia.
Departs Simpson Lagoon, Alaska, late August-early September; Bathurst Island early September; and Victoria Island, Baffin Island, and Melville Peninsula mid-September. First sightings in late September-early October along Atlantic Coast; major sightings in November along northeastern coasts; 7.4-7.8 loons per hour 5-18 November at Manomet Point, Massachussets; 8,262 individuals observed 14 November 1996 at Avalon, near Cape May, New Jersey; more than 50,000 counted there every autumn, the timing correlated with onset of mid-arctic deep cold. On West Coast, late August-early November, peaking late September and October (British Columbia; Oregon.
Routes Of Migratory Movements
Small numbers past Alaskan and Yukon Beaufort Sea coasts, large offshore counts, and regular inland sightings suggest fall movements overland across Mackenzie River valley to Pacific Northwest. Throughout shelf waters of ne. U.S. in spring, but farther inshore in fall. Annual sightings of large numbers in Bay of Fundy and November peaks over Cayuga and Seneca Lakes, New York, point out importance of these routes; the latter may represent flights from staging sites on Lake Ontario, where thousands congregate. Inland movements border Lake Ontario, moving west in fall, turning south to w. Pennsylvannia, and crossing eastward across Pennsylvania to East Coast.
Flies in flocks of about15, low (5-70 m) over coastal waters along Atlantic Coast at 50-70 km/h, higher (1,000-1,700 m) and faster inland. Along Pacific Coast, often flies just behind breaking waves. Hundreds in Delaware Bay move together with tide along rips to feed on fish and crabs (Callinectes sp.), then fly up-current to drift back again. Usually migrates in loose aggregations; rare observations of overland V-formations.
Thanks to Barr, Jack F., Christine Eberl and Judith W. Mcintyre. 2000. Red-throated Loon (Gavia stellata), The Birds of North America Online (A. Poole, Ed.),species 513.
Migratory and dispersive. Freshwater breeding lakes deserted in autumn; winters on tidal water, mainly inshore. From Spitsbergen, most depart September, virtually all by early October. In Lapland and Russia, autumn movements begin when young capable of strong flight (usually late August), continuing until final exodus when fresh waters freeze about October. Has occurred off Kola Peninsula in December. Arrives Black Sea September-November, though some still passing through Ukraine December; Spring passage away from winter quarters during April and May, or March on western seaboard, when moves to northern fjords, estuaries, and bays awaiting inland thaw; reappears on Greenland and Spitsbergen lakes May and early June; present off Murmansk coast from late April but May or June before return to tundra lakes. British breeding lochs occupied mainly April to September-October.Principal wintering areas in Europe: Atlantic and North Sea coasts around Britain and Ireland and from western Norway at least south to Brittany, with smaller numbers in Kattegat and Baltic, Black and Caspian Seas; small minority penetrate south into Bay of Biscay and, in cold winters, Mediterranean. Migration routes not well known. 4 recoveries birds ringed Greenland (west and east coasts) all from west Europe: south Norway (Kristiansand), England (Essex, Kent), and inland France (Dordogne). 2 Swedish chicks found midwinter in France (Seine Maritime) and Netherlands; and 2 chicks from Scotland (Shetland) also found French coast (Finistère, Vendée); 2 full-grown birds ringed Gulf of Bothnia, Finland, recovered Kent and north Russia (Tumen); latter suggests that, as in better-known case of Black-throated Diver G. arctica, part of USSR population migrates to or through Baltic area, though presumed Russian and west Siberian birds also winter Black and Caspian Seas. Possibly some from island populations disperse pelagically without long-distance migration: one Icelandic breeder recovered Icelandic coastal waters January. Occasional summer records from North and Baltic Seas presumably non-breeders. A few winter on larger lakes of central Europe (e.g. Switzerland), but many inland winter records probably sickly or storm-blown birds.Migrates by day and night, usually in ones and twos, occasionally small parties. Large numbers may occur in loose associations on favoured staging waters, but no Palearctic records comparable to that of 1200 on Lake Ontario, Canada, in October.
Thanks to BWP on CDRom