On 6 December the ADU held its 4th Citizen Science Day for 2014, meeting at the National Botanical Gardens in Pretoria.

This event gave me the opportunity to arrive a day earlier and survey the weaver colonies at the CSIR. In just under 5 hours of walking back and forth over the north part of the campus, 61 colonies were found of 3 species.

Number of colonies by species:
47 Southern Masked Weaver
12 Thick-billed Weaver
2 Southern Red Bishop

The Southern Masked Weaver nests were mostly in trees, including fever trees, other acacia trees, and other trees or bushes. Single colonies were found in a jacaranda, mulberry, pin oak, and a pine tree, with a few colonies in London plane trees. No nests were in reeds.

Two old nests of the Southern Red Bishop were found in the reeds at the dam. Several males in breeding plumage were seen.

The Thick-billed Weaver has increased in number of nest sites, compared to nearly 20 years ago. Most nests were around the dam and also at the wetland. The constructed wetland had one pond with water, while the other ponds were dry at the time of the survey (unlike nearly 20 years ago, when they were all full). Interestingly a few nests were in trees. Two old nests were far from water, and one of the nests was an old breeding nest.