CSIRO Publishing blank image blank image blank image blank imageBooksblank image blank image blank image blank imageJournalsblank image blank image blank image blank imageAbout Usblank image blank image blank image blank imageShopping Cartblank image blank image blank image You are here: Journals > Emu   
Emu
http://www.birdlife.org.au
  A Journal of BirdLife Australia
 
blank image Search
 
blank image blank image
blank image
 
  Advanced Search
   

Journal Home
About the Journal
Editorial Board
Contacts
Content
Online Early
Current Issue
Just Accepted
All Issues
Special Issues
Research Fronts
Rowley Reviews
Sample Issue
For Authors
General Information
Notice to Authors
Submit Article
For Referees
Referee Guidelines
Review an Article
Annual Referee Index
For Subscribers
Subscription Prices
Customer Service
Print Publication Dates

red arrow Complete Archive
blank image
With the complete digital archive of Emu now online, we have selected some of the most interesting and significant papers for readers to access freely.

blue arrow e-Alerts
blank image
Subscribe to our Email Alert or RSS feeds for the latest journal papers.

red arrow Connect with BirdLife
blank image
facebook TwitterIcon LinkedIn

red arrow Connect with CP
blank image
facebook twitter youtube

 

Article << Previous     |     Next >>   Contents Vol 100(5)

Patterns and Correlates of Bird Migrations in Sub-Saharan Africa

Philip A. R. Hockey

Emu 100(5) 401 - 417
Published: 2000

Abstract

The common mode of migration among Afrotropical birds is movement from tropical to temperate areas to breed usually coinciding with the onset of summer and the rainy season. The proportion of species that are migratory can be predicted with considerable accuracy from the average temperature of the coldest month of the year. Once this exceeds 20˚C, 90% or more of breeding species will be non-migratory. The likelihood of any one species being migratory is strongly influenced by diet, foraging mode as influenced by the behaviour of prey and vegetation geography. Insectivores are disproportionately well represented among the migrants whereas, at the other extreme, frugivores are almost exclusively sedentary. Within the insectivore guild, the greatest migratory tendencies are found among those groups that exclusively hunt aerial insects above the canopy (e.g. swallows, swifts and night-jars), perch-hunters that depend on large, active insect prey (e.g. halcyonid kingfishers and rollers) and taxa heavily dependent on the larvae of flying insects (cuckoos). Insectivores that hunt or glean small invertebrates (volant or not) within the canopy or glean relatively sessile prey from the ground are much less likely to be migratory. This gradient, linking prey attributes and hunting behaviour to migratory behaviour, is probably mediated by a parallel gradient in seasonal prey availability. In marked contrast to the Neo-tropics and the Orient, many Afrotropical birds undertake polarised migrations, with part of the population moving north, and part south, of the tropics. The explanation of this is hypothesised to lie in the spatial symmetry and large extent of savannas both north and south of the tropics, coupled with a lack of north-south dispersal barriers. These conditions are not replicated in either the Neotropics or the Orient.



Full text doi:10.1071/MU0006S

© Royal Australian Ornithologists Union 2000

blank image
Subscriber Login
Username:
Password:  

 
PDF (303 KB) $25
 Export Citation
 Print
  
    
Legal & Privacy | Contact Us | Help

CSIRO

© CSIRO 1996-2014