Social Structure and the Development of Helping Behaviour in the Bell Miner (Manorina melanophrys, Meliphagidae)

Authors


Dept. of Genetics and Human Variation, La Trobe University, Bundoora, Victoria 3083, Australia.

Abstract

The hypothesis that bell miners (Manorina melanophrys) improve their alloparenting skills during the period spent as helpers was tested by means of comparing: a) the frequency of nestling care activities, b) the frequency of nestling attendance “mistakes”, c) the gizzard contents and items brought to nestlings, and d) interactions at the nest with the breeders, for helpers of different ages. Results show that young birds made fewer feeding visits to the nestlings and made more empty (i.e. non-feeding) visits than older helpers. The few “mistakes” detected were also made by young helpers. The proportion of food items brought to the nestlings consisting of arthropods was smaller for very young helpers (≤ 3.8 months) than for older helpers. Sexually mature helpers also had relatively more arthropods than psyllid sugary covers (a food item very easy to locate and capture) in their gizzards than immatures in winter, but this difference was marginally not significant.

Young helpers must learn their place within the group hierarchy, but no clear division of labor in the alloparental activities studied was detected, which might have increased the effect of learning during the period birds spent as helpers.

Ancillary