Leaf stripping in weavers

Gardeners are sometimes frustrated by weavers stripping leaves from their trees or bushes. Early theories suggested that bare twigs would prevent snakes from reaching weaver nests as there would be insufficient grip. But arboreal snakes can still reach nests relatively easily. Another theory suggested that stripping leaves would reduce wind resistance and cause the nests to sway less. This suggestion has not been taken seriously as the nests still sway dramatically in high winds, with little difference between bare or leafy twigs. Since the leaf-stripping habit makes a colony more visible, the most plausible theory is that this allows the displaying male to be more visible to nearby females. This appears to be true for the polygynous weavers, where males display from their nests and try to attract as many females as possible. However, some monogamous weavers (with established pair bonds) also strip leaves near their nests, although this could make their nests unnecessarily visible to predators. Before investigating further, here is a list of weavers that have been recorded to remove leaves.

Note: weavers also pick leaves to use as nest material – in this case one or a few leaves are nipped off and taken to the nest. The leaf stripping behaviour is very different – a weaver nips off many leaves in an area (usually close to the nests, but sometimes also further away), and lets them drop to the ground or water.

Table. Weavers which have been recorded stripping leaves

The Southern Masked Weaver is well known for its leaf-stripping behaviour. Males spend a high proportion of their time building nests during the early and mid (peak) breeding season, but this wanes at the end of the season. Leaf stripping rates, however, show a different pattern and are high in the early and late parts of the season, and slightly lower during the peak season. Leaves are usually stripped in bouts of several minutes.

The incidence of leaf stripping varies greatly, and in some weavers leaf stripping occurs in certain nesting sites and not in others. The Spectacled Weaver, for instance, strips leaves when nesting in bushes and trees, but not when nesting in fir and palm trees, while Village Weavers do strip leaves around their nests when nesting in palm trees.

Southern Red Bishops and Thick-billed Weavers sometimes gnaw off the tops of the reeds or sedges in which they nest. This may make the nests slightly more visible from above the reedbeds.

A record of leaf stripping by a male Large Golden Weaver appeared to be part of his display to a female. Interestingly, the malimbes where leaf stripping has been observed, was generally done by the female.

Weavers sometimes strip leaves far from their nests, or even where no nests are present. This suggests that this is a displacement behaviour. Leaf stripping is less energetically costly than collecting nest material for nest building.

In conclusion, weavers strip leaves around their nests to make them more visible, but in other situations this is a displacement activity. It may also play a role in courtship, although this does not seem to be common.