NATURAL SELECTION ON BILL CHARACTERS IN THE TWO BILL MORPHS OF THE AFRICAN FINCH PYRENESTES OSTRINUS

Evidence for natural selection on seven bill and body characters is examined in the two bill morphs of the African estrildid finch Pyrenestes ostrinus. Two regression methods are used in examining natural selection in association with survivorship: a parametric (Lande and Arnold, 1983) and a non-parametric (Schluter, 1988) method. Selection was estimated in adult males, females and juveniles over a four-year period in a population in south-central Cameroon. Selection was common among groups but patterns differed and depended on the method used in detecting selection. The non-parametric method revealed evidence for disruptive selection occurring on bill width and is explained within the context of known feeding efficiencies and the hardness of important seeds in finch diets. Directional selection was common on bill characters in all groups, but infrequent on other characters. There was no evidence of selection on generalized size or shape characters. Selection on bill characters was common across groups despite low annual variation in rainfall. This contrasts with studies of Galápagos finches in which selection is frequently associated with dramatic changes in food supply caused by high variance in annual rainfall. Patterns of selection on bill traits in P. ostrinus also differ from those in song sparrows and Galápagos finches by exhibiting evidence for natural selection on all bill dimensions.     

NOTES ON THE GENUSUSNEADILL. EX ADANSON

Usnea quercinaBystrek & Górzyńska, based on heterogeneous type material, is lectotypified and becomes a synonym ofU. wirthiiP. Clerc.Usnea wirthiiis new for South America. A distribution map ofU. madeirensisMotyka (Syn.U. silesiacaMotyka) in Europe is given.Usnea hesperinaMotyka (Syn.U. elongataMotyka,U. schadenbergianaGöpp & Stein,U. subgracilisVain.,U. subplicata(Vain.) Motyka) is new for Africa, Asia and South America.Usnea hirta(L.) F. H. Wigg. (Syn.U. corrugataMotyka,U. foveataVain.,U. leprosaMotyka) is new for Africa.Usnea subscabrosaNyl. ex Motyka (Syn.U. santae-annaeMotyka) is new for South America. The holotype ofU. marocanaMotyka (=U. mutabilisStirt.) was found in LBL.     

2. NOTES ON THE MASKED WEAVER

Radiotelemetry is an important tool used to aid the understanding and conservation of cryptic and rare birds. The two bird species of the family Picathartidae are little-known, secretive, forest-dwelling birds endemic to western and central Africa. In 2005, we conducted a radio-tracking trial of Grey-necked Picathartes Picathartes oreas in the Mbam Minkom Mountain Forest, southern Cameroon, using neck collar (two birds) and tail-mounted (four birds) transmitters to investigate the practicality of radio-tracking Picathartidae. Three birds with tail-mounted transmitters were successfully tracked with the fourth, though not relocated for radio tracking, resighted the following breeding season. Two of these were breeding birds that continued to provision young during radio tracking. One neck-collared bird was found dead three days after transmitter attachment and the other neither relocated nor resighted. As mortality in one bird was potentially caused by the neck collar transmitter we recommend tail-mounted transmitters in future radio-tracking studies of Picathartidae. Home ranges, shown using minimum convex polygon and kernel estimation methods, were generally small (<0.5 km²) and centred around breeding sites. A minimum of 60 fixes were found to be sufficient for home range estimation.     

NOTES ON THE BIRDS OF SOUTH-EASTERN NIGERIA.

A systematic account (with field-notes) of the birds of south-eastern Nigeria is given, based on a collection of about 350 skins made between 1946 and 1949, mainly in the neighbourhood of Owerri. The range of several species is extended by new Nigerian records and the distribution of the races of other species more clearly defined.