PHOWN Newsletter 2
27 Jan 2011
PHOWN has exceeded 550 records since its start on 29 July 2010. Some top contributors have been Arnia van Vuuren (7 weaver species, mostly Southern Masked Weaver colonies), Tony Archer (5 weaver species, mostly Southern Masked Weaver and White-browed Sparrow-Weavers colonies) and Crystelle Wilson (mostly Village Weaver colonies). There are now records from all South African provinces. More records from other countries would be welcome.
Featured species: Spectacled Weaver
The Spectacled Weaver is locally common in parts of southern and eastern Africa. It is a solitary species, and pairs often nest at the same site every year. The male may be distinguished from the female by a black bib. Sometimes nests from previous seasons hang near new nests. The nest is usually built by the male but sometimes the female helps. Unlike polygynous weavers which often build a nest in a day or two, the Spectacled Weaver may take 2-3 weeks to complete its nest which has a long entrance tunnel. Nest height varies from 1-7 m above the ground. Egg laying may be as long as two months after the nest is completed. Sometimes a pair will raise two broods in a season - the same nest or a new nest may be used.
The entrance tunnel is usually 10-20 cm long but may be more than 60 cm long. By taking photos from the side of the nest and submitting to PHOWN, it may be possible to estimate the length of the tunnel from the photo. This way a large sample may be obtained of tunnel length, so please do look out for Spectacled Weaver nests! Pairs may remain near their nests during winter, so it is also worthwhile checking to see if the birds roost in their old nests during winter (if you are fortunate enough to have them breeding in your garden!).
To see all the Spectacled Weaver records in PHOWN, see here (14 records currently).
Interesting recordsOne of the most unusual nest sites submitted since the previous newsletter is of Cape Weavers nesting on a water tank (VM 489). This record from the West Coast National Park was reported by Graham, Taylor and Carla Fiford.
The first Chestnut Weaver in South Africa was seen in the Northern Cape in January 2011 (article due to appear in Ornithological Observations soon, see also News item here). A week later a male was seen in Tswalu busy nest-building. Usually this species is colonial, and there were no female Chestnut Weavers for this particular male, but still a great record to be submitted to PHOWN by Tony Archer (VM 502).
There are many other interesting submissions. For instance, Southern Masked Weaver chicks visible in the entrance of their nest (VM 514), an interesting nest of Holub's Golden Weaver (VM 317), and eggs of the Southern Brown-throated weaver (VM 343). There are more interesting photos and records but you will need to browse through the Virtual Museum to find them!
Analysis: colony sizes
Currently the top species are Southern Masked Weaver (n=168) and Cape Weaver (n=134), and this provides enough records to compare some basic breeding attributes for these two species.
The histogram shows that most Southern Masked Weaver colonies have less than 10 nests, and colony size decreases rapidly, although sometimes there are large colonies. Incidentally, larger colonies usually have several males in the colony while smaller colonies have a single male. Cape Weavers show a gradual decrease in colony size. This is also reflected in the averages: Southern Masked Weavers have 7.1 nests per colony on average and Cape Weavers have 21.4 nests per colony on average (see here).
SummariesThere are some improvements in viewing summaries. You can now see a thumb-nail of all your records. Go here and choose your name and hit go (your name may appear several times with different additional observers, but all your records will be shown). You can click on any thumb-nail to see the full record details. In addition, on the observer summary page you will see a map showing the localities of all your records. Again you can click on "Hybrid" to see the satellite imagery as well. If you find any errors, please do send corrections.
There are some special categories that you can browse. Go here and choose a category and hit go. An interesting one is colonies along national roads. The map of colonies shows the route between Johannesburg and Durban clearly! Many of these colonies are at ultra-shells and other garages, while some are colonies next to the road. So next time you go on holiday (or business) record some weaver colonies along the way.
Finally...Over the next few months breeding activity will decrease in South Africa as winter comes. If you have withdrawal symptoms, you can travel to the more arid areas to record Sociable Weaver and White-browed Sparrow-weaver colonies as these birds stay at their nests year round, even if they are not breeding year round. With the large amount of rain (and floods), some weavers (especially Southern Masked) may continue to breed for longer than normal, so do look out for that. You can also take part in other Virtual Museum projects if you don't have any active weaver colonies in your area. Many weaver species north of southern Africa will start breeding in the next few months.
Thanks for your participation! Continue to send in records. This year the Animal Demography Unit (ADU) is celebrating 20 years of citizen scientists! Do visit the ADU home page to read the Editorial by Director of the ADU, Les Underhill, listing some of the events planned for this year. In particular, there will be two "citizen science biodiversity weeks": 23–31 July and from 29 October–6 November, to record as many Virtual Museum records as we can.
Email: weavers4africa [at] gmail.com