Warming threat to migratory birds

Red knot chicks born under rapidly warming conditions in the Arctic are now smaller when they migrate, hampering their ability to reach the best food in their wintering grounds in West Africa. Researchers warn that body shrinkage could also be affecting the survival of other Arctic migrants

Taimyr Peninsula, Russia Snow in red knot breeding grounds melting progressively earlier, at
rate of half a day per year

DATE OF SNOW MELT

1985 1995 2005 2015 Jun 20 Jun 30 Jul 10 Jul 20

Red knot (Calidris canutus canutus)

Newborn red knots depend on “bloom” of insects that follows melt of tundra for main food supply. Climate change is pushing bloom earlier and out of sync with red knot hatching

Banc d’Arguin, Mauritania Smaller birds born in warm Arctic summers arrive in wintering grounds with shorter beaks, which prevent them from reaching quality mollusc (1) deep in sand

Birds forced to subsist instead on lower quality molluscs (2) and seagrass (3), hampering survival

Burial depth (mm) 0 10 20 30 40 50 60

1. Loripes 30-40mm

2. Dosinia 15-30mm

3. Zostera 10-20mm

Source: Science Magazine Picture: Newscom