Behaviour and Ecology
Bird behavoural ecology
Ecology of the white-crowned black wheatear (Oenanthe leucopyga) - Kate Durrant
Around the town of St Katherine, nestled in a bowl created by the beautiful Sinai mountains, many species of birds can be found inhabiting the gardens maintained by the Bedu. Many pass through on migration, but a few species remain all year. The most recognisable is the WCB wheatear, or Baga’a as the Bedu call them. They live in apparently permanent territories. We have established a colour-banded population of Baga’a, and have been studying their behaviour, ecology and life history. We invite MRes students, or self-funded PhD candidates, to apply to continue field work in this remote but stunning region, and build up our knowledge of this fascinating little bird.
Stone rampart building
The oddest thing about the Baga’a is their nesting habits. They build a standard cup-shaped nest, placed in a rock crevice. So far, so good. Before this, the female collects hundreds of tiny flat stones and lays a pavement, or rampart, from the front of the rock crevice right underneath the nest cup. Our research has shown that there can be thousands of stones, all similar in shape, perhaps gathered over many seasons. Why do this? There are several competing theories, which we are currently trying to unravel. It may be for predator protection, or for thermoregulation: there are many possibilities. Building the rampart also imposes a cost on the female: could it be a test of her quality?
Male Baga’a have a varied repertoire of calls and song. They can mimic other bird species in the area, such as the Scrub warbler (Scotocerca inquieta) and Tristram’s grackle (Onychognathus tristamii). They have unusual, potentially aggressive, ‘white rump’ displays, and an incredible ‘dance flight’ that they perform for their female prior to mating. We do not yet have a good grasp on the timing and function of any of these behaviours. The Baga’a also sports, as its English name suggests, a white crown. This only develops in their third year, and potentially gives a reliable way to age birds for the first few years of their lives. Birds can breed when still in black-crowned plumage, and females especially seem to be black-crowned in a greater proportion of their lives. Does crown colour have a role in signalling age and quality? Are old birds indeed ‘good’ birds?
Baga’a are common, ideal for a field-based project. They respond very quickly to any improvement in environmental conditions and produce several broods each spring. They are intimately connected with the lives of the Bedu (see below), but are also found breeding in more remote wadis (dry river beds). The secret appears to lie in being a food generalist, but their diet is poorly known. Little is known about feeding of chicks and fledglings, which remain dependent for a period of time. Over the longer term, we know little about their survival strategies and lifetime reproductive success, and nothing about territory turnover.
Interactions with humans
The Baga’a are a great favourite of the local Bedu, our hosts and guides in Sinai. The birds have a ‘confiding’ nature similar to European robins (Erithacus rubecula). A Baga’a is always welcome in a bedouin garden - those with white crowns are called ‘birds of happiness’. No matter how tough the times, the Bedu try to spare some water and food for their avian friends: they have many folk tales about the Baga’a, including stories of how they have saved people’s lives by warning them of approaching snakes. What is it that enables a species to become so well adapted to living with humans? Is there a genetic correlate shared with other species, such as robins, that allows them to prosper from the generosity of humans? Is this a learned behaviour, and can any species accomplish this trick?