A boreal songbird's 20,000 km migration across North America and the Atlantic Ocean

Length polymorphisms at two candidate genes explain variation of migratory behaviors in blackpoll warblers (Setophaga striata)

“…Avian migration involves a suite of complex behavioral and physiological responses to exogenous seasonal cues including changes in diet and metabolism, the onset of migratory restlessness ( zugunruhe ), and precise directional orientation (Bairlein, Eikenaar, & Schmaljohann, ; Berthold, ; Gwinner, ; Jenni & Schaub, ). The culmination of these responses allow individual birds to accomplish amazing migratory feats, sometimes flying over ocean for several days at a time or navigating thousands of kilometers through unfamiliar habitat between wintering and breeding grounds (Bairlein et al, ; Battley et al, ; DeLuca et al, , ; Gill et al, ; McKinnon, Artuso, & Love, ). Each of these behavioral and physiological responses is likely genetically inherited (Berthold & Pulido, ; Helbig, ; Liedvogel & Lundberg, ; Pulido, Berthold, Mohr, & Querner, ) and could be under natural selection (Gienapp, Leimu, & Merilä, ; Nilsson, Klaassen, & Alerstam, ; Pulido & Berthold, , ).…”

“…Blackpoll warblers breed across the North American boreal forest from Alaska to Newfoundland and in isolated montane fir forests at the southern periphery of their range in northeastern United States (Figure ; DeLuca et al, ). Annual blackpoll warbler migration between the northern breeding grounds and wintering grounds in the Amazon basin of northern South America is one of the longest migratory routes for any North American songbird (DeLuca et al, ; Morris et al, ), and was recently tracked from geographically distant breeding populations using light‐level geolocators (DeLuca et al, , ; Figure ). Birds depart the wintering grounds in mid‐April to mid‐May and travel through the Greater Antilles and continental United States to their northern breeding territories, a trip that can vary in duration considerably depending on breeding location (mean 34 days, range 17–49 days; DeLuca et al, ).…”

“…Annual blackpoll warbler migration between the northern breeding grounds and wintering grounds in the Amazon basin of northern South America is one of the longest migratory routes for any North American songbird (DeLuca et al, ; Morris et al, ), and was recently tracked from geographically distant breeding populations using light‐level geolocators (DeLuca et al, , ; Figure ). Birds depart the wintering grounds in mid‐April to mid‐May and travel through the Greater Antilles and continental United States to their northern breeding territories, a trip that can vary in duration considerably depending on breeding location (mean 34 days, range 17–49 days; DeLuca et al, ). After departing the breeding grounds in August through October, blackpoll warblers first migrate southeastward to the Atlantic coast of United States and Canada, then migrate south over the Atlantic Ocean to their South American wintering grounds, a nonstop trans‐oceanic flight of up to 3,000 km that may take up to three days (DeLuca et al, , ).…”

“…Birds depart the wintering grounds in mid‐April to mid‐May and travel through the Greater Antilles and continental United States to their northern breeding territories, a trip that can vary in duration considerably depending on breeding location (mean 34 days, range 17–49 days; DeLuca et al, ). After departing the breeding grounds in August through October, blackpoll warblers first migrate southeastward to the Atlantic coast of United States and Canada, then migrate south over the Atlantic Ocean to their South American wintering grounds, a nonstop trans‐oceanic flight of up to 3,000 km that may take up to three days (DeLuca et al, , ).…”

“…Breeding distribution (dark gray) and fall migratory route (light gray with dashed outline) for blackpoll warblers following DeLuca et al (). Sample location is shown with black circles with sample sizes in parentheses.…”