Náttúrufræðingurinn - 1953, Side 23

ÍSLENZKIR FUGLAR VI
131
(Pholis gunnellus) virðist vera uppáhaldsfæða hennar hér við land,
en hann heldur sig eins og kunnugt er aðallega á 0—15 m dýpi. Við
Breiðafjörð gengur sprettfiskurinn lika oft undir nafninu teistufiskur
eða teistusíli. En teistan lifir einnig á ýmsum öðrum fiski, svo sem
marhnút, sandsíli og uppvaxandi kola. Og talið er, að hún lifi einnig
á krabhadýrum, lindýrum og ormum.
SUMMARY
Icelandic Birds VI. The Black Guillemot (Cepphus grylle (L)J.
In Iceland the black guillemot is a fairly common and widely distributed breed-
ing bird, which in the breeding-season frequents rocky and boulderstrewn coasts
and islands. Owing to the scarcity of suitable nesting sites it is comparatively rare
on the fiat south coast, but on all other coasts it is a common breeding bird. The
eggs are laid in crevices or fissures in low rocky cliffs or among or under masses
of loose rocks or boulders and never at a great height above sea level. Occasionally
the eggs are deposited in natural holes in rocky soil or turfy talus slopes, but the
black guillemot never excavates burrows like the puffin. In the Breidafjördur
archipelago, where the black guillemot is a very common breeding bird, it frequ-
ently nests in stone fences or even stone walls of buildings. In drift-wood areas in
North-Iceland it is also reported to breed occasionally in piles of driftwood. In the
bird cliffs proper, on the other hand, the black guillemot is scarce. This is obviously
due to the fact that it generally avoids high, perpendicular cliffs. And further-
more in the bird cliffs as well as in the talus at their base, the black guillemot
meets in the puffin (and to a lesser degree in the razorbill) a serious competitor
for nesting sites, and as the puffin breeds earlier it mostly gets the upper hand.
The black guillemot thus has to be content with sites left over by the puffin, and
f°r 0x18 reason tllc two species generally do not breed in mixed colonies. The black
guillemot nowhere breeds in as big colonies as the puffin, the common guillemot
and Brunnich s guillemot. Often there are only a few pairs together, or individual
pairs may even breed separately, but in the biggest colonies the number of breed-
ing pairs may however amount to several hundreds.
The black guillemot lays 2 eggs. Much more infrequently the clutch consists of
only 1 egg and a clutch of 3 eggs has never been recorded in this country. The
eggs mostly rest on bare rock or gravel and there are no signs of a nest hollow.
Thus there is hardly a question of any nest being built although in some cases a
few pebbles or shell fragments seem to have been arranged underneath the eggs.
Ihe eggs are usually so well hidden away in crevises or under loose rocks that they
are not visible from the outside, although in some cases they may just be perceived
in the dimness of the nesting hole. Usually they can only be reached with difficulty
with the hand without clearing away some stones. The eggs are laid in the first
half of June, and the clutch is often not complete until the middle of that month.
As far as is known the black guillemot is a sedentary bird in Iceland. All the
year round it is not uncommon along the coasts, often quite close to the shore.
It is, however, not impossible that a part of the Icelandic population of this species
may recede from the shore to the outer shelf in midwinter, but nothing is known
for certain about this. And however this may be, it is a fact that outside the breed-