You can now find the latest breeding information for every weaver species on PHOWN (Photos of Weaver Nests). This means that you can: (i) look up published info here, and (ii) compare the published info with that in PHOWN, especially data on colony sizes and breeding seasonality. There is already improved data in PHOWN on colony sizes in some weavers.

For Southern Brown-throated Weaver, for instance, the Handbook of the Birds of the World, Vol. 15 (HBW) gives the following: "Colonial, with up to 300 nests together" and data currently in PHOWN gives colony size as 2-15 nests, mean 9.3 (n=3). Similarly, for the Lesser Masked Weaver, HBW says: "Colonial, up to 60 nests at a site", while PHOWN provides much improved information: 5-65 nests, mean 22.3, for 6 colonies. Again, for Yellow Weaver, HBW gives "Colonial; in reedbeds seldom more than 50 nests together, but 150 nests in tamarind tree (Tamarindus) on Zanzibar" while PHOWN provides the following information: 3-64 nests, mean 27.3, for 18 colonies.

No species has enough data yet - more records are needed for all species to study variation in colony size geographically and in different years. Records from long ago can be submitted if you have a photo, GPS location, and date (nest count and other data is preferable but if you don't have this, still submit the record). To browse records and find out about submitting records, read here.