An account is given of the topography, climate and vegetation belts of Nigeria to illuminate the ecology of the Palaearctic migrants to the country.
The faunistic relationship of the resident and migrant avifauna is considered and it is shown that approximately one species in six is migrant. It is shown that the more arid vegetation belts support the largest numbers of migrant species, the forest belt supporting only very few species. Some species appear to overfly the most northern areas.
Rather few observations of visual migration are available but those known are recorded. A summary of ringing recoveries affecting Nigeria is given and it is shown that there is clear evidence of species returning to the same wintering grounds each year.
The status of 135 migrant species is briefly treated and other species are mentioned where negative information is valuable.
Calandrella rufescens, Cyanosylvia svecica, and Emberiza hortulana, notmentioned by Bannerman (1930-53) are included and Cettia cetti is recorded from West Africa for the first time. Several species have had their range extended to include Nigeria.
A comparison of breeding areas with the Mediterranean/Sahara crossing zones and Nigerian occurrences shows that most terrestrial species in Nigeria move fairly closely to the lines of longitude. Many aquatics, mostly herons and ducks, breed much to the east of the longitude of Nigeria.
It is suggested that the unexpected number of Palaearctic migrants which winter in the arid north of Nigeria indicates that food is less scarce than the appearance of the country in the late dry season indicates. There is a great need for an ornithological and ecological research station in Nigeria in an area such as southwest Lake Chad.