28/1/00 Between 3 and 4pm at Montrose Basin redshank were seen
feeding in an unusual manner. They were on the rising tide in an oval
shaped group of 25-30 birds. The members of the group were
very close together - only a few inches between each bird. They were
feeding in water that reached up to their belly feathers. The feeding
action was reminiscent of avocet with a short side-to-side scything
motions of the bill with the head submerged to the eye level and sometimes
beyond. After 4-5 scyths each bird raised its head and swallowed the
prey with a few quick gulps with the bill and then immediately resumed
the scything. The nictitating membrane could be seen covering the eye
(giving them a white eye) as they submerged the head.
Occasionally redshank, in ones and twos, flew in to join the group.
This group moved along the shore keeping to the same depth of water and
took about 20 mins to cover 150 metres feeding all the time.
The group then broke up and flew back to their starting position
and joined other redshank in the water and formed three groups
(15-20 birds in each group) which adopted the same feeding action.
This time the birds were in deeper water (up to the flanks).
After a further 15-20 minutes the groups broke up.
All the time this was happening, redshank were feeding in the normal way
on the exposed mud above the advancing tide - 2m between birds
and probing the mud in a relaxed way. These birds were only 10-20m
away from the "frenzy" groups in the water but seemed to ignore them.
I have not seen this mode of feeding before and would be interested if anyone has witnessed this behaviour. It would be interesting to know what the prey species was but it was too small to see even at the closest approach - Corophium shrimp is the obvious guess. Whatever it was it must have been suspended in the water as they were not deep enough to probe the mud.