In recent weeks Philip Veerman has posted 3
messages on an intriguing event: large congregations of Swallows/Martins over
the eastern Part of Lake Burley Griffin. It sounded very much like a
pre-roosting gathering. Philip provided me off-line with further information as
to when and where this event took place (thank you Philip for this).
However, by the time I got my act together and
went to see for myself, things had changed considerably and there were fewer
birds. On the evening of the 25th Jan. I estimated about 1000
birds: no longer ?mainly Welcome Swallows?, but exclusively Tree Martins. Also a
Hobby tried his luck in catching
one. Around sunset all birds suddenly went down and disappeared out of sight, I
assumed that they had gone into the reeds along the lake for roosting. I
returned to the site well before sunrise next morning, to see only about 4 Tree
Martins high up in the sky later in the morning. Clearly that part of the lake was not a
roosting site.
I went again on the 28th to watch for
the evening ?Martin spectacular?, but all I saw were 4 Tree Martins first moving north, returning about 10
min later, then going again north 5 min later. This probably indicates that
either the conditions that favoured the larger congregations no longer exists,
or that the masses of Tree Martins/Swallows have passed
through.
Michael
Lenz
