Literature review to assess bird species connectivity to Special ...

2.2 Black-throated diver
2.2.1 Foraging
Maximum foraging range
There is little quantitative information available on foraging ranges of black-throated
diver. In Britain, breeders commonly fly between breeding lochs and coastal sites
that may be “several kilometres away” (Jackson, 2003). In taiga of Northern Russia,
where fishing was poor, birds were reported to travel to feeding lakes 5–10km from
the nest site (Cramp, 1977). Pairs breeding on North Lewis have been recording
flying approximately 7-8km whilst brood-rearing (Andrew Stevenson pers. comm.).
Studies in North-west Scotland and the Western Isles have found foraging range to
be associated with chick age (Jackson, 2003). Foraging excursions that occur after
the chicks were four days old (the post-brooding phase) tended to be to more distant
feeding sites, but typically still within 2km of the brood (Jackson, 2003).
Likely foraging destination
Feeding mainly occurs on the breeding loch, occasionally on surrounding lochs and
exceptionally at nearby coastal sites among Scottish breeders, (Jackson, 2003).
Likely route of foraging flights
No specific information has been found on the likely routes of foraging flights.
Observations suggest that flight routes and heights are similar to those of redthroated
divers (Andrew Stevenson pers. comm.).
2.2.2 Nesting
No additional information pertinent to connectivity, was found.
2.2.3 Post-breeding roosts
Roosts have been recorded between July and September involving non-breeding
and post-breeding birds. Such a roost was recorded on North Uist holding a
maximum of 15 birds, which is likely to include birds breeding at least 4-5km away
(Fuller, 2003).
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