Migratory To Sedentary

Over a wide range of latitudes, many bird populations have become more sedentary over recent decades. Prior to 1940, the Lesser Black-backed Gull Larus fuscus was almost entirely migratory in Britain, only a few individuals remaining year-round. But nowadays large numbers of all age groups stay for the winter, feeding mainly on refuse dumps which have increased the winter food supply (Hickling 1984). A similar change has occurred among Herring Gulls Larus argentatus in Denmark (Petersen 1984). Another example is the Eurasian Blackbird Turdus mer-ula, in which the British and mid-European populations have become progressively more sedentary during the last two centuries, as winters have mellowed (Berthold 1993, Main 2000). In both Europe and North America, many seed-eaters are now wintering further north in their breeding range, in association with the provision of suitable food at garden feeders (Table 21.1). Among many other short-distance and medium-distance migrants, increasing numbers of individuals now winter in areas where they once were wholly migratory, these species developing into typical partial migrants. Some such changes could be genetic in nature, others facultative. Their net effect is to expand the winter avifauna of many high-latitude regions.

Table 21.1 Examples of recent changes in migration patterns. Excludes changes in timing of migration described in the text.

A. Shortening of autumn migration to winter nearer breeding areas

Cape Gannet Morus capensis

Great Cormorant Phalacrocorax carbo Bewick's Swan Cygnus columbianus bewickii Greylag Goose Anser anser

Bean Goose Anser fabalis

Greater White-fronted Goose Anser albifrons

Snow Goose Chen caerulescens

Canada Goose Branta canadensis

Red-breasted Goose Branta ruficollis

Red-crested Pochard Netta rufina

White-tailed Sea Eagle Haliaeetus albicilla Sharp-shinned Hawk Accipiter striatus

Early ring recoveries of South African ringed birds from West Africa, but no recent recoveries, perhaps because fisheries discards in the Benguela upwelling region now allow them to stay south, nearer their breeding areas Shortening of migrations in the Baltic Sea region

Rare in Poland until 1960s. Now regular migrant and winter visitor

Wintering grounds changed from Spain to the Netherlands, a previous region of stopover. Similar shortening of migration route in eastern Germany

In the nineteenth century large numbers wintered in Britain, now mainly in Germany-Netherlands

Gradual shortening of migration of north European and west Siberian birds to give greater proportions wintering in continental areas and smaller proportions in Britain Historically wintered primarily in Louisiana, Texas and Mexico. Many now winter further north in rice-growing areas of Iowa, Nebraska, Missouri and Arkansas

Formerly wintered mainly in the southern tier of States, now winters mainly in the middle tier of States

Used to winter in Egypt (illustrated in tombs), but now confined to more northern latitudes

Increasing proportion of population wintering in central, as opposed to southwest, Europe

Swedish birds used to winter in southeast Europe but, after winter food supplied, now stay in Sweden

Now remaining in northeastern breeding areas in North America, and declining at migration sites further south, associated with increased garden bird feeding and more northern wintering of prey species

Oatley (1988)

Schmidt (1989)

Tomiatojc (1990)

Nilsson & Persson (1993), Rutschke (1990)

Hestbeck et al. (1991)

Houlihan (1986), Kear (1990) Keller (2000)

Helander (1985)

Viverette et al. (1996)

Various waterfowl

Merlin Falco columbarius

Great White Egret Egretta alba Black-crowned Night Heron Nycticorax nycticorax Squacco Heron Ardeola ralloides

Common Crane Grus grus

White Stork Ciconia ciconia

Lesser Black-backed Gull Larus fuscus

Eurasian Chiffchaff Phylloscopus collybita Great Reed Warbler Acrocephalus arundinaceus Bluethroat Luscinia svecica

Number of species wintering in Lithuania increased from 17 in the 1940s to 42 in the 1990s, and total numbers increased from several thousands in the 1930s to 150 000 in the 1990s. This was due largely to reduction in migration distance (shown by ringing), with smaller proportions reaching western Europe. It was especially obvious in Mallard Anas platyrhynchos and Mute Swan Cygnus olor Northern boundary of winter range extended northward into the Canadian prairies

Increasing proportion wintering in mid-latitudes of western Europe Increasing proportion wintering in southern Europe and North Africa as opposed to sub-Saharan Africa

Increasing proportion wintering in southern Europe and North Africa, as opposed to sub-Saharan Africa

West European population formerly wintered in Spain-Morocco, now winters mainly in France-Spain and eastern Germany. Following construction of the dam at Lac du Der (Champagne, northern France) cranes started to use this site as a major stopover, and also as a wintering area, thus shortening their migration by about 1500 km each way

Formerly wintered entirely in Africa, thousands are now wintering regularly in the Mediterranean region, notably Spain, Bulgaria and Israel. Progressive reduction in migration distance of birds breeding in eastern Europe during the 1950s-1980s as shown by winter ring recoveries in Africa

Winters further north in Europe. Was a summer visitor to northern Europe but over last 40 years changed, so that large numbers now winter

Increasing proportion winter in Britain

Formerly wintered entirely in Africa, south of the Sahara. Some now wintering in Spain

Increasing proportion wintering in Spain as opposed to sub-Saharan Africa

Svazas (2001)

Marion et al. (2000) Pineau (2000)

Hafner (2000)

Alonso et al. (1991) and others

Berthold (1996), Fiedler (2003)

Hickling (1984) Lack (1986)

Bermejo & de la Puente (2004)

Yellowhammer Emberiza citrinella Eurasian Bullfinch Pyrrhula pyrrhula

European Greenfinch Carduelis chloris

Evening Grosbeak Hesperiphona vespertina

Hooded Crow Corvus corone cornix

Increasing proportion winter in Finland Increasing proportion winter in Finland

Increasing proportion winter in Finland and Sweden

Winters much further north than formerly in response to garden bird feeding

Much reduced numbers wintering in eastern England now than in the nineteenth century, attributed to greater proportion of European birds wintering further north and east, confirmed by ringing

B. Shortening of spring migration to breed nearer wintering areas

Whooper Swan Cygnus cygnus Barnacle Geese Branta leucopsis

Increasing numbers now breed in Poland, about 800 km southwest of main breeding range of that population Breeding population established on Gotland and other sites around the Baltic and in the Netherlands, thus shortening migration to Novya Zemlya by 1300 km, or more. Birds from a different population have also started to breed in Iceland, thus shortening migration to Greenland by more than 500 km

C. Change in direction to establish new wintering area

Greater White-fronted Goose Anser albifrons

Black Stork Ciconia nigra

White Stork Ciconia ciconia

Little Egret Egretta garzetta

Change in wintering sites from central Europe to the Netherlands and western Germany associated with a directional change of 15° to give a new route along the Baltic coast Re-colonised west Europe in 1970s-1980s probably from eastern populations. These birds started migrating southwest through Gibraltar, whereas eastern European populations migrate southeast through the Bosphorus

The descendents of birds that started breeding in South Africa in 1933 have been shown by satellite-tracking to migrate northward for about 3000 km in the non-breeding season Southern European birds migrate south, often across the Sahara. Many now move northwest to winter in northern France and southern Britain. Most of these birds are now resident in these areas

Väisänen & Hildén (1993) Väisänen & Hildén (1993)

Root (1989)

O'Donoghue, in Wernham et al. (2002)

Tomiatojc & Stawarczyk (2003)

Larsson et al. (1988), Forslund & Larsson (1991)

SvaZas et al. (2001)

G. Neve, in Sutherland (1998)

Underhill (2001)

Marion et al. (2000)

Blackcap Sylvia atricapilla Some central European birds switched from migrating southwest to winter in western Mediterranean area to migrating north or northwest to winter in Britain Shore (Horned) Lark Colonised northern Europe in the mid-nineteenth century (1847) and

Eremophila alpestris then some thought to have started migrating southwestwards to winter around North Sea

D. Change from migratory to resident population

Great Crested Grebe Podiceps cristatus

Mute Swan Cygnus olor Canada Goose Branta canadensis

Red Kite Milvus milvus Eurasian Blackbird Turdus merula

Eurasian Chiffchaff Phylloscopus collybita

Great Tit Parus major Common Starling Sturnus vulgaris

Increasing proportion in the Netherlands has become resident

From the first record in 1955, up to 2000 birds now winter near their breeding areas in Lithuania

Birds from migratory North American populations introduced to Britain have become resident, apart from newly developed moult migration

Increasing proportion in Scandinavia has become resident Formerly wholly or mainly migratory in mid-latitudes of western Europe, now mainly resident

First recorded in 1846, the numbers wintering in Britain have increased greatly since 1940. They include some local birds and some migrants from Europe which may indicate a change in direction Once-migratory population in the Finnish city of Oula near the Arctic Circle is now resident, following food provision by householders Central European populations have become partially resident, with increasing numbers staying in towns in winter

E. Change from resident to migratory population

Canada Goose Branta canadensis

Cattle Egret Bubulcus ibis Common Starling Sturnus vulgaris

Birds introduced to Scandinavia winter in increasing numbers on north Polish coast

Migration system has arisen in North America, and between Australia and New Zealand (2000 km)

Birds introduced into North America from British resident population have become migratory over much of continent

Berthold et al. (1992a)

Gätke (1895), Glutz von Blotzheim & Bauer (1985)

Adriaensen et al. (1993) SvaZas et al. (2001) Wernham et al. (2002)

Kjellen (1992) Berthold (1993, 1999), Main (2000)

Green, in Wernham et al. (2002)

Orell & Ojanen (1979)

Merkel & Merkel (1983), Berthold (1993)

Polish ringing scheme

Root (1989), Maddock & Geering (1994) Kessel (1953), Dolbeer (1982)

House Finch Carpodacus Resident population introduced to eastern North America became mexicanus migratory in less than 30 years, with different migration directions

(south-southwest) from west to east across the breeding range European Serin Serinus serinus As spread north in Europe, switched from being resident to migratory

F. Establishment of breeding population in former wintering range

Leach's Storm Petrel Now breeds on islands off South Africa

Oceanodroma leucorhoa

Manx Shearwater Puffinus puffinus Now breeds on west side of Atlantic, in former migration area White Stork Ciconia ciconia Started breeding in South Africa in the 1933. Now regular. Winters in the tropics of Zaire and Rwanda European Bee-eater Merops Thousands now breed in South Africa apiaster

G. Lengthening of autumn migration

Great White Pelican Pelecanus onocrotalus

Pink-footed Goose Anser brachyrhynchus

Red-breasted Goose Branta ruficollis

Chaffinch Fringilla coelebs

Shifted wintering sites following development in the Nile delta in Egypt to further south

Population has shifted in Britain to wintering in large numbers in southeast England, associated with decline in food supply further north

Shifted wintering grounds from Azerbaijan to Romania and Bulgaria following habitat changes

Vast predominance of females in flocks in southern England in late eighteenth century changed to more equal ratio in late twentieth century

Based partly on Sutherland (1998).

Able & Belthoff (1998) Berthold (1999)

Harrison et al. (1997)

Storey & Lien (1985) Harrison et al. (1997)

Harrison et al. (1997)

Vangelewe & Stassin (1991)

Wernham et al. (2002)

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