Temporal and spatial patterns of abundance and breeding activity of Namaqua sandgrouse in South Africa

ENGLISH ABSTRACT: We examined various measures of temporal and spatial patterns of abundance and breeding activity of Namaqua sandgrouse Pterocles namaqua (presumably mostly for P. n. furvus) in South Africa. Bird-atlas maps indicating reporting-rates and extensive-counts showed that the majority of Namaqua sandgrouse concentrate in Bushmanland, in the north-western Cape Province, from December to March. From April to July the sandgrouse move north and east of Bushmanland and apparently return to Bushmanland from August to November. This west-east movement occurs at a relatively constant rate of 30-50 km per month. Only 15% of the sandgrouse ringed at an estate within the eastern part of this species range returned the following winter. Follicle diameter and brood-patch measurements increased significantly from July to August, at the time when the majority of birds leave the estate. Belly-soaking was more prevalent in early summer in Bushmanland than in any season in the east. South African populations of Namaqua sandgrouse are partial migrants which breed primarily in early summer (October - November) in Bushmanland. ****************** AFRIKAANSE OPSOMMING: Temporale en ruimtelike patrone in verspreiding en broei aktiwiteite van die Namaqua sandpatrys pterocles namaqua (vermoedelik meestal P. n. furvus) is ondersoek in Suid Afrika. Die vo latlaskaarte wat rapporteerskale en ekstensiewe-telling wys, het aangedui dat van Desember tot Maart die meerderheid sandpatryse gekonsentreer is in Boesmanland. Van April tot Julie het die vo lsreeds noord en oos beweeg, net om terug te keer na Boesmanland van Augustus tot November. Die oos-wes beweging na, en vanaf Boesmanland vind plaas teen 'n relatiewe konstante 30 -50km per maand. Slegs 15% van die geringde sandpatrysee wat geoorwinter het op 'n landgoebdinne die spesie se oostelike verspreidings gebied, het teruggekeer die opeenvolgende winter. Follikeldeursne en broeistrookmetings het beduidend vergroot vanaf Julie tot Augustus, gedurende 'n periode wanneer die meerderheid vo ls die landgoed reeds verlaat het. Pensdeurweking wasmeer dominant in die vroe somer in Boesmanland as gedurende enige ander seisoen in die ooste. Die Namaqua sandpatrys populasies in Suid Afrika is gedeeltelik migreerders wat hoofsaaklik in die vroe somer (Oktober - November) in Boesmanland broei.