-----Opprinnelig melding-----
Fra: Wim Vader
Sendt: 11. mars 2006 12:13
Til:
Kopi: birdchat; Sabirdnet ; birding-aus
Emne: Galapagos, a dream come true.5
My sincere apologies: I accidentally sent out this one before correcting my
many typos. Please throw the earlier one out!
Wim
GALAPAGOS, A DREAM COME TRUE.5. THE SMALL BIRDS (NO
WONDER DARWIN GOT CONFUSED!)
The Galapagos islands and Charles Darwin's visit there on the Beagle in the
1830's are justly famous in the history of evolution, and the endemic finches
(Geospizidae) occurring here (12 spp in the Galapagos archipelagi, nr 13 on
Cocos Island off Costa Rica) are now generally known as Darwin's finches.
In reality Darwin was during his visit mostly interested in the differences
between the large tortoises from the different islands, as well as those among
the mockingbirds. He did collect also a largish series of the finches, which he
thought contained representatives from three different families of birds, nbut
he mixed up his collections from the different islands. Gould, the
ornithologist who described the Beagle's birds, could only untangle the mix
with the help of smaller but more exactly labeled, series of finches collected
by Captain Fitzroy himself, and by Darwin's assistent in the field, the young
sailor Sym Covington.
When arriving at Baltra airport, we had no luggage, so all had to buy sunhats
and T-shirts in the many small shops outside. Here we soon got to know the
darwin's Finches, and to realize that they are indeed an utterly confusing
bunch. A flock of them scrounged like sparrows round the airport buildings and
the shops, and they look and behave indeed quite sparrowy, although all are
conspicuously short-tailed, as if a cat had got their tail. The adult males are
all black, the females and immatures sparrowy brown, and stripy underneath.
Unfortunately this short colour description is valid for 6 of the 12 galapagos
species!! Four more have also similar females, but here the males are
black-hooded rather than all black. In the last three both sexes have the
female colouration, although somewhat less stripy underneath. Add to this that
the species often occur in mixed flocks and that the subtle differences in bill
shape and size vary from island to island, and I don't blame Darwin at all for
confusing the critters. After 10 days, with the help of expert guidance and
good fieldguides, I am still quite wobbly and tentative in my identifications.
The birds themselves are not to blame; they are as tame as most Galapagos birds.
The finches divide into Large, Medium and Small Ground Finches (males all
black, and especially the last two quite common most places and often in mixed
flocks), and Large and Common Cactus Finches (males again all black, but these
birds, indeed often found on cactuses, have narrower and more pointed beaks).
The names already give an inkling that identification might well be tricky. The
last all black species is the Sharp-beaked Finch of the northern islands, the
famous 'vampyre finch', which we sadly failed to see at Genovesa; as it name
says, it has a still more sharp beak.
Then there are Large, Medium and Small Tree Finches (and yes, they may also
forage on the ground, and the ground finches in the trees!), with black-headed
adult males, and also the very large-beaked Vegetarian Finch has a black-headed
male. The small Warbling Finch (which Darwin though was some sort of warbler)is
comparatively easy to recognize, it flits warbler-like through the trees, is
quite common on most islands where there is sufficient cover, and also has a
weak little warbler-like trilling song. The Mangrove Finch is the rarest of
all, and we never found one, but we did several times come across the famous
Woodpecker Finch, one of the very few tool-using birds. It too is more easy to
recognize, it is somewhat lighter in overall colour, and forages nuthatch-like
along the stems and branches of the trees and among its epiphytes. I had hoped
to see it using a cactus spine to probe for wood-boring insects, the trick for
which it is justly famous, but had to be content with the next best thing,
seeing one fly off with a spine in its beak----already a memorable moment!
These finches are everywhere on the islands, they fuss and scrounge like
sparrows in the villages and the sidewalk cafés, they are found among the sea
lions on the sandy beaches, as well as in the Scalesia forest, and among the
large tortoises in the highlands. And for me they are still quite confusing!
Much much easier is the situation among the parulids, the New World Warblers.
No 'confusing fall warblers' here, every warbler you spot, from the intertidal
to the top of the volcanoes, is a Yellow Warbler, of the resident Galapagos
race. They are everywhere, from the intertidal (I wonder what they eat there,
they forage a lot intertidally, among the sandpipers and plovers) to the lava
fields, the Scalesia forests, the farming belt and the highlands. They give
vivid flashes of yellow in an otherwise often somewhat bleak terrain, and they
have a very pleasant little song strophe, which every time I hear it, reminds
me of the european Willow Warbler, although it is definitely more upbeat.
The other quinessential small birds of the Galapagos are the mockingbirds,
definite personalities. As Darwin already realized, there are clear differences
between the mockingbirds of the different islands. They have now been divided
into 4 species, of which one the Charles Mockingbirds, now is almost extinct.
It is now confined to two small islets, of course inaccessible to birders. So
we went through the archetypical birders ritual, of circling the islets in
panga, until we saw the silhouette of the mockingbirds on top of one of the
large Opuntias; close enough to see that this was an unmistakable mockingbird,
but I should think not really close enough to see all the subtle differences
between these and the other Galapagos mockingbird species. Still, we all
congratulated each other and solemnly ticked a new lifebird! It is easy to
understand that birders seem a bit strange to many people! There are no such
problems with the funny Hood Mockingbird, also an endemic on the island of
Española (Hood); these birds come flying towards you as soon as you enter the
group territory and almost beg for water, being not averse to inspecting your
backpack thorougly in the process. All these mockingbirds have a large variety
of call, which they may jumble together to a rather unmelodious, but somehow
quite cozy song. They are widespread and common, although usually not numerous.
This almost completes the list of small birds in the Galapagos. Not quite:
there are two tyrannid flycatchers, the showy red Vermilion Flycatcher of the
highlands, and the more subdued and again very tame Galapagos Flycatcher, which
may be found anywhere. We encountered one during a walk over lava fields, in an
area virtually without any plant growth at all.
There is also an endemic swallow, the Galapagos Martin, but they are very thin
on the ground; Riet got the honour to discover the only one we saw during this
trip. And there are two very small rails, which we never got to see; Moorhens,
on the other hand, popped up many places, both in the highland lakes and swamps
and in the brackisk coastal lagoons.
A little bit larger are the endemic Dark-billed Cuckoo, another bird we never
saw (the drought?), and the introduced Smooth-billed Anis, which have become
quite common in the farm belt in the highlands. Here they share the dominance
with another newcomer, the Cattle Egret, which has already mamanged to become
surprisingly numerous many places in the highlands. A fitting emblem of the old
and new era in the Galapagos was the sight of a Cattle egret riding on the back
of a Giant tortoise!
Wim
Vader, Tromsø Museum
9037
Tromsø, Norway
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