Migrant Stopover Ecology of Birds in Arid Environments: Case Studies in North American and Middle Eastern Desert
Investigators (most current known information)
Migratory birds pose greater conservation challenges than any other fauna assemblage worldwide. These species have specific habitat requirements on breeding and wintering grounds and migratory stopover sites, they migrate thousands of kilometers crossing international and continental borders to reach winter breeding locations, and face large scale habitat alterations in all three areas. Protection afforded migratory birds varies dramatically among the countries they cross, and language and cultural barriers among countries makes large scale, comprehensive management plans difficult. As a result, few studies have addressed conservation needs of birds during migration, these species must navigate large expanses of hostile terrain such as deserts, oceans and large inland bodies of water. It is during these periods that birds are most vulnerable due to the tremendous energy demands combined with lack of suitable habitat to stop, rest and refuel or lack of sufficient food resources for refueling. In particular, there is a need for a better understanding of how different species cross arid environments so that management plans can incorporate this knowledge and identify potential sites important for species during their intercontinental migratory flights. In this study we focus on avian migration through desert environments for birds crossing between breeding and wintering grounds in the Neartic-Neotropical and Paleartic-Ethiopian regions and the resulting conservation implications. Specific objectives related to this research problem include:
- To determine how migrants cross desert environments.
- To quantify the proportion of long and short distance migrants.
- To examine the importance of habitat quality and resource availability at stopover sites.
- To determine if select species are diurnal or nocturnal migrants.
- To determine if species differ in migration timing or habitat use by age class and sex.
Study sites will consist of blocks of potential migratory habitat such as grassy waterways (including rivers, irrigation canals and oases), agricultural hedgerows and open patches of desert scrub and desert grasslands. We will examine how different species cross desert environments including whether they attempt to cross in one non-stop flight or through a series of short flights that involve stopping to rest and refuel by comparing the diversity and relative abundance of species using stopover habitat with those killed by collisions with radio towers during migrations in North America (an unbiased sample of nocturnal migrants) and those stopping to refuel after crossing the Red Sea in Israel, which will represent virtually every migrant species using the area. We will set up laboratory experiments on migratory restlessness and time of day of this behavior to determine if some species travel during the day as opposed to the more common nocturnal flights. The importance of stopover sites, habitat type and habitat quality will be investigated in the Chihuahuan Desert of the United States through weekly surveys of avian abundance and diversity as well as measures of vegetative structure and composition and food resource availability. At sites in the United State, Israel and Jordan birds will be aged through skull ossification and blood samples will be collected to use genetic techniques to sex birds so that differences in migration timing or habitat use by age class and sex can be identified. Management plans need to incorporate what habitats are important for migratory birds in arid environments, how birds utilize the habitat as they cross deserts, if they do so differently by age and sex class or by the length of their migratory flight.
No outcomes reported