THE CHANGING BIRDLIFE ON TROMSØYA 2
When we moved to Tromsø in 1973, the Greenfinch Chloris chloris did not occur
there at all; the northermost occurrences were in S. Senja, some 200km south of
here. Now, in 2012, the Greenfinch is probably the most numerous passerine on
the island, and the species occurs commonly all the way to the Russian border,
1000km N and E of here.
This is an example, and maybe the most conspicuous, of the gradual changes in
our avifauna which I have experienced in these thirty years. It is an easy
conclusion in such cases to cry Global Warming, but that may often be too easy.
In the case of the greenfinches the extensive planting of conifers in gardens
and spruce plantations in the area may well also have played an important role,
just as I think that that may have been the main reason for the increase of
nesting Goldcrests in our area and elsewhere in the outer regions of N. Norway.
But global warming no doubt does play a role. The mean temperature here has
increased during these thirty years, and research by my colleague Rob Barrett
has shown that many summerbirds now arrive in the mean 1-2 weeks earlier than
they did 40 years ago. And quite a number of southern birds have during these
30 years established themselves in Tromsø. Chiffchaffs Phylloscopus collybita
used to be scarce, but now they are common This last year I have seen regularly
Blue Tits Parus caeruleus in my garden and once even a Winter Wren Troglodytes
troglodytes, and in Folkeparken, the remnant birch wood with planted spruce and
pines, I now hear every year the crystal flute of the European Robin Erithacus
rubecula, and the insistent songphrase of the Wood Pigeon Columba palumbus,
birds one earlier had to go to Troms inland (south of here) to see and hear.
Several people around here have also reported Jays Garrulus glandarius, an
other southern resident bird slowly making its way north. In all these cases
the increase in temperature seems a logical explanation for the gradual move
northwards.
In some other cases the background may well be a different one. Grey Herons
have started to nest on the island, and are now a common sight on the shore. In
this case cessation of persecution may well be an important factor; these
herons nested north of here long before they came to Tromsøya. We also have
some few pairs of Collared Doves Streptopelia decaocto; they arrived as early
as 1969, at the tail end of their impressive march through entire Europe, and
they have been able to hang on, although seemingly only just, partly because an
old lady feeds them in winter.
Another newcomer, and the spark to this report, is the Black-tailed Godwit.
These are the Icelandic subspecies, and a few birds have since the late sixties
gained a toehold in N.Norway, and since then have spread in small numbers
through the area. We have also got more breeding Greylag Goose Anser anser, but
that seems to be an all-European trend.
It is much harder to decide that a species has decreased in numbers, but we
have a few instances of that also. In the seventies the lek of the Ruffs at
Tisnes consisted of 40-50 birds; now we may be content if there are 10. And the
Slavonian (Horned) Grebe has disappeared from many of the small lakes in the
area. I also have the impression that I much more seldom hear the yodeling
voice of the Long-tailed Duck, when Riet and I walk the shore in the winter
twilight at Christmas time, but here again my decreasing hearing may play a
role. And there are no Garden Warlers Sylvia borin in Folkeparken anymore, but
that may mainly be due to the excessive zeal of the park people, who are
allergic to wild undergrowth.
I hope this was close to half as fascinating for you, as all these developments
have been to me.
Wim
Vader, Tromsø Museum
9037
Tromsø, Norway
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