Bird communities at two marshes in Øvre Forra, today and 40 years ago

Abstract

In the protected area Ovre Forra in Central Norway, birds were surveyed at two marshes in two succeeding years at the beginning of the 1970s. By following the same survey procedure 40 years later in these unchanged marsh habitats, I sought changes in the breeding bird community. While the total number of waders seems to have been quite stable, the abundance of some of the involved species might have changed during this period of time. Due to low numbers, and annual variations, the implications for some of the involved species have to be taken cautiously. The most abundant species in Ovre Forra is now the Common Redshank Tringa totanus . This species has outnumbered the earlier most abundant species in this bird community, the Meadow Pipit Anthus pratensis . The numbers of the Meadow Pipit, Northern Lapwing Vanellus vanellus , European Golden Plover Pluvialis apricaria and Common Sandpiper Actitis hypoleucos all tend to be lower than for 40 years ago. The Common Gull Larus canus and two Tringa species, the Common Redshank T. totanus and Common Greenshank T. nebularia , seem to have increased in numbers, while the situation for the Common Snipe Gallinago gallinago and the Whimbrel Numenius phaeopus appears to be stable. The Ruff Calidris pugnax used to be a characteristic species on the Ovre Forra’s bogs in the 1970s, but has since vanished. Altogether, the study shows an apparently quite stable avifauna over the time span of 40 years in this environmentally stable reserve.