Hi all,
Just a short comment on shearwaters (and a plug for more contributors to
the Australian Seabird Group Beach Patrol Scheme!). Whatever has affected
Short-tailed Shearwaters is not a local event (e.g. small hydrocarbon
spills in St Kilda), as there are records of large numbers dying in much of
eastern Australia and in New Zealand. What is also interesting is that
whatever has happened has not effected any other species (except perhaps
for early reports of Wedge-tailed Shearwaters in NSW), as in Tasmania and
New Zealand apparently numbers recorded of other species (such as Sooty
Shearwaters) are normal.
There have also been suggestions that this is just a normal event and
nothing to worry about. Is this reasonable? In the last week in southern
Tasmania we have surveyed 14 km and counted 665 Short-tailed Shearwaters (a
rate of 47.5/km), while there are other reports of hundreds on other
beaches (and large numbers floating dead in the channel). (From what I have
read on birding-aus, this sounds typical of what other people are finding.)
Fortunately, there is data in the Australian Seabird Group Beach Patrol
scheme that can be compared with this result (see below). From this it
would appear the rates birds are being encountered is very high compared to
previous years. Nevertheless, the data for comparison is rather thin on the
ground, so I would encourage anyone who feels the urge to help the ASG
beach patrol scheme and have regular pleasant strolls on the beach. They
should get in touch with me and I will help join them up.
Why are the birds dying? I don't know. But several I weighed were very
light (about 400g c.f. 500-550g on return according to HANZAB). We have
sent a collection off for post-mortems, but haven't got the results yet.
Perhaps there was some problem with foraging in the Northern Hemisphere (La
Nina? global warming? who knows?) this past winter in the areas that the
Short-taileds were foraging in.
Hope this was of interest,
tim.
Below are the results for the Australian Seabird Group Beach Patrol scheme
for three areas for the month of October:
Southern Tasmania
year distance (km) birds rate (birds/km)
1993 14 20 1.43
1994 3 2 0.66
1995 5 5 1.00
1996 4 0 0.00
1997 4 0 0.00
1998 6 2 0.33
1999 25 20 0.80
Otways (Victoria)
year distance (km) birds rate (birds/km)
1993 22 3 0.14
1994 21 117 5.57
1995 22 4 0.18
1996 25 25 1.00
1997 27 100 3.70
1998 2 0 0.00
1999 20 10 0.50
Northern New South Wales
year distance (km) birds rate (birds/km)
1993 0
1994 99 576 5.82
1995 68 2 0.03
1996 12 7 0.58
1997 28 1 0.04
1998 34 3 0.09
1999
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