Page 42 - Brighetti1979

SUMMARY - Mediterranean Shearwater - Calonectris diomedea diomedea

.Distribution. Partially sedentary and breeding in the islands and islets of the Mediter-
ranean, the Tyrrhenian and the middle Adriatic seas. It usually breeds not far from
sea leve! and has been noticed up to 130 m. The present situation ricords good
presences in the islands surrounding Sicily, where the species is considered more nume-
rous than Puffinus puffinus. Breeding is known for the Egadi, Eolie and Pelagie islands
(wh ere recent sightings indicate colonies of hundreds of pairs), Pantelleria, Ustica? and
Maltese lslands ( various and sizable _colonies). Regarding to the middle Tyrrhenian Sea
scarce information is known about 'the Pontine Islands and breeding is considered to
be possible in other nearby islands. In the numerous islands of the Tuscan Archipelago
breeding is confìrmed for some of them and probable or possible for others. As for
Sardinia, few colonies are known and certainly many others are stili to be visited. In
fact the sightings of big flocks are frequent and regular during the summer period and
near suitable environments, particurarly in the extreme northern and southern areas.
As for Corsica there are certain records for some localities (severa! tens of pairs) and
clues for others in the northern and western areas ; quite recently 8 sites have been

.discovered, with a total population estimated at 390 pairs ( ± 50). As for the middle

Adriatic Sea, colonies are known for the Tremiti lslands, where breeding was known
in ancient times. In generai the frequent and regular observations already of specimens
(sometimes in very numerous flocks) during the breeding season and near localities fìt
for breeding indicate that a good dea! of colonies have not yet been found. A very wild
.estimate gives a total of some thousands of pairs (perhaps less than 6-7.000).
Among limiting factors we can remenber the ever growing disturbance caused by
tourism and pleasure craft navigation, the picking of eggs and chicks and the direct
killings o fadult by fìshermen and hunters for alimentary purposes or to use the belly
down as a bait for fìshing. The cohabitation with rats ( Rattus sp.) does not appear to
produce evident damages, while the one of Larus audouinii does not appear to produce
any negative effect. Some specimens are sometimes killed by birds of prey (presumably
Falco peregrinus). In the Maltese lslands, until some years ago, military bombings caused
:noticeable damages to the nestings grounds and the specimens themselves.
Movements. Partially migrant (late August/November and late February/March) they
also make dispersals and winter wanderings especially following sea currents and looking
for new feeding grounds or following big schools of fìsh on the move. Gatherings of
noticeable size are known during the winter period for the eastern coasts of Tunisia
(Gulf of Gabes), where in autumn a migratory movement takes piace from the north
towards the south, and in spring in the opposite direction. Part of the population of
the islands surrounding Sicily and also of the lower and middle Tyrrhenian Sea
.converges in the lower Mediterranean Sae. It is known that a little part of the specimens
spends its wintertime near the colonies, especially in the upper Tyrrhenian ones.
A bird ringing campaign in the Maltese lslands (1965-1978) undertaken by The Ornitho-
logical Society, has made possible to ring 640 specimens; 12 recoveries have been recor-
ded, confìrming the habit to come back to the colonies of birth, even after years. The
species has also accidentally appeared along rivers and lakes of some inland areas of
-.the continent.

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