SESAW Newsletter 1, 27 Sep 2010
SESAW has been running for a year now, and it has been helpful to receive data on a monthly basis to monitor progress and check for data accuracy. Weavers are breeding again so please ensure that you record male plumage and female brood patches.
The top ringed species are the Southern Masked Weaver and the Southern Red Bishop and these two species have recapture rates of 7 and 12% respectively. Some of the top weaver ringers are Grant Egen, Margaret McCall and Alan Brooks, but all contributions are valuable: an important aspect of the project will be to compare survival rates across the region, from Namibia through North-West, Gauteng and KZN to the Western Cape.
I have been ringing many weavers on the Cape Peninsula. I have not included these totals on the web yet because I'm experimenting with ringing at many different localities to see how how far weavers normally move - movements would affect survival analyses. Cape Weavers seem to move much more than the other weavers on the peninsula, although the adults (at least males) stay near their colonies through the breeding season.
To see the value of recording male plumage and brood patch, here is a quick analysis of retrap rates for the four weaver species with most data. The first data column shows the total retrap rate for all age and sex classes, the second column shows the retrap rate for all adult males and females, and the third column shows the retrap rate for adult males in full breeding plumage (BP) and females with brood patches (bp).
|Species || All || Ad m || Ad f || Ad m, full BP || Ad f, bp |
|Village Weaver || 8.1 || 11.3 || 12.1 || 22.7 || 10.3 |
|Cape Weaver || 10.7 || 28.7 || 5.4 || 29.5 || 3 |
|Southern Masked Weaver || 7.7 || 11.8 || 9.7 || 12.8 || 13.2 |
|Southern Red Bishop || 12 || 14.5 || 7.2 || 18.6 || 7.3 |
The overall retrap is low due to including immatures that may move more than adults. Columns 2 and 3 have much higher retrap rates. The plumage and brood patches should still be recorded as the survival analysis may be different for Columns 2 and 3. Also this table does not include birds in Column 3 that have been retrapped in winter (when not in full BP or with a bp).
Thanks for your participation! Please continue to send data regularly and send any outstanding data.
See any weaver nests at your ringing sites? Take a photo, a nest count and submit the record to PHOWN