Seasonal variation in migration strategies used to cross ecological barriers in a nearctic migrant wintering in Africa

Abstract

Ecological barriers such as oceans, mountain ranges or glaciers can have a substantial influence on the evolution of animal migration. Along the migration flyway connecting breeding sites in the North American Arctic and wintering grounds in Europe or Africa, nearctic species are confronted with significant barriers such as the Atlantic Ocean and the Greenland icecap. Using geolocation devices, we identified wintering areas used by ringed plovers nesting in the Canadian High‐Arctic and investigated migration strategies used by these nearctic migrants along the transatlantic route. The main wintering area of the ringed plovers (n = 20) was located in western Africa. We found contrasting seasonal migration patterns, with ringed plovers minimizing continuous flight distances over the ocean in spring by making a detour to stop in Iceland. In autumn, however, most individuals crossed the ocean in one direct flight from southern Greenland to western Europe, as far as southern Spain. This likely resulted from prevailing anti‐clockwise winds associated with the Icelandic low‐pressure system. Moreover, the plovers we tracked largely circumvented the Greenland icecap in autumn, but in spring, some plovers apparently crossed the icecap above the 65°N. Our study highlighted the importance of Iceland as a stepping‐stone during the spring migration and showed that small nearctic migrants can perform non‐stop transatlantic flights from Greenland to southern Europe.

A red knot as a black swan: how a single bird shows navigational abilities during repeat crossings of the Greenland Icecap

“…northern wheatear Oenanthe oenanthe leucorhoa , Bairlein et al ; purple sandpiper Calidris maritima , Summers et al ; and ringed plover Charadrius hiaticula psammodromus , Léandri‐Breton et al ) suggest that most of these birds follow geographic loxodromes like the geese. However, some of the observed northward tracks suggest that individuals cross the Greenland Icecap above 65°N latitude, along routes that may approach orthodromes (Summers et al , Léandri‐Breton et al ). Unfortunately, the tracks end prematurely because the light‐based geolocators used in these studies did not allow for estimation of locations under the constant daylight conditions present above the Arctic Circle during northern summer.…”

Shorebirds wintering in Southeast Asia demonstrate trans-Himalayan flights

“…Birds crossing such barriers may face physiologically harsh conditions such as extreme temperatures and humidity, or greatly reduced oxygen levels, and these routes can be energetically demanding and lack refuelling opportunities 1 . Crossing barriers may be aided by factors such as wind support, and result in a shorter migration distance and time, and be more energy efficient overall 1 , 5 – 8 . Detours to avoid barriers can reduce risks and although migration distances are typically longer 3 , birds may also benefit from favourable winds, and be able to refuel during stopovers and not need to store heavy fuel reserves to the same extent 1 , 3 , 4 .…”

Autumn migration strategy of juvenile great reed warblersAcrocephalus arundinaceuson the eastern European flyway: a spatiotemporal pattern of accumulation and utilisation of energy stores

“…Migrants may divide their journey into short steps and replenish fat reserves on several stopover sites, or they may cover the majority of the distance (in extreme cases, even the whole route) without refuelling, utilising the energy stores gained prior to migration (Biebach 1990;Schaub & Jenni 2000a). Migration strategies may vary even among closely related species that cover similar distances between the breeding and wintering grounds (e.g., within the genera Sylvia, Acrocephalus and Phylloscopus; Ożarowska 2015;Stępniewska et al 2018;Sander et al 2019), among the populations of the same species depending on the flyway they follow (e.g., the garden warbler Sylvia borin; Bairlein 1991) or even at the intra-population level (e.g., the common ringed plover Charadrius hiaticula; Léandri-Breton et al 2019). The amount of accumulated energy stores at stopover sites determines the ability of individuals to undertake the migratory flight (Newton 2008;Schmaljohann & Eikenaar 2017) and it may be used to calculate the possible distance they are able to cover by estimation of potential flight ranges (Pennycuick 2008).…”