Primary moult patterns and morphometrics in the Green-winged Pytilia Pytilia melba (original) (raw)
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A Study of Moult-Site Fidelity in Egyptian Geese, Alopochen aegyptiaca , in South Africa
African Zoology, 2013
Little is known about moult and moult-site fidelity of African waterfowl. Satellite telemetry and uniquely engraved colour-rings were used to study moult-site fidelity of Egyptian geese marked at two sites in South Africa -Barberspan in the summer-rainfall region and Strandfontein in the winter-rainfall region. Twelve Egyptian geese were tagged with satellite GPS PTT transmitters while moulting at Barberspan and Strandfontein during 2008 and 2009, and a further 527 were colour-ringed between June 2007 and March 2009. Bi-monthly point counts of Egyptian geese and scans for colour-ringed birds were made at each study site from resulting in 139 individually colour-ringed geese being re-sighted during the study period. We explored Egyptian geese dispersal distances away from the study sites and modelled moult-site fidelity from colour-ring return rates corrected for survivorship, sampling period efficiency and colour-ring detectability estimates. There were 12% and 29.7% colour-ring return rates for geese ringed at Barberspan and Strandfontein, respectively. Four of five moulting birds tagged at Barberspan with satellite transmitters returned to Barberspan to moult the following year. Two of these same birds moulted at Barberspan in the third year while the other two moulted elsewhere. One out of seven Egyptian geese satellitetagged at Strandfontein returned to the same site to moult the following year. One bird moulted at a nearby pan (5 km away), two moulted at estuaries less than 30 km from Strandfontein and one bird moulted at a farm dam 56 km away. Two birds satellite-tagged at Strandfontein did not moult the following year and returned to moult at Strandfontein in the third year. The moult-site fidelity model suggested that a minimum of 16% of Barberspan birds and 51% of Strandfontein birds returned to the same wetland to moult the following year. The apparent low moult-site fidelity at Barberspan suggested by colour-ring resightings may reflect the small number of birds colour-ringed at the site.
Estimates of bird numbers through quantification of density and range sizes are necessary for decisions regarding conservation status, yet counts of birds are often confounded by uncertainty of detection. The status of the endemic birds of the fynbos biome is of interest due to their conservation value in a global biodiversity hotspot, the ecological services they provide, and their importance for the avitourism industry. We conducted an extensive repeated point count survey in 2013 across the fynbos biome, South Africa, to determine probability of detection and covariates of site occupancy for 27 bird species, including 6 fynbos endemics. Detection of most species was influenced by time, temperature or vegetation height. Important covariates influencing site occupancy were vegetation height, altitude, time since fire and habitat type. Site occupancy for four fynbos endemic species was positively associated with increasing altitude. We further conducted point counts and mist-netting in eastern regions of the fynbos to calculate local density and standardized capture rates. A linear regression analysis showed that capture rates were a function of bird densities, but that several species were captured at higher rates than expected, notably nectarivorous species. During mist-netting a relative abundance count was conducted. We expected deviation of the fit of the regression of capture rates on relative abundance to correlate with detection probability, as we expect this index to underestimate skulking and cryptic species, but there was no correlation. Estimated species richness indices were highest for the biome-wide survey, and lowest for mist-netting due to the body size limit posed by the capture technique. Overall, point counts are an effective method for surveying birds in the fynbos and mist-netting can be used to create an index of relative abundance for smaller species, but this can be affected by subjective placement of nets.
Second Southern African Bird Atlas Project (SABAP2): Progress report to 6 December 2012
Ornithological Observations, 2012
Ornithological Observations accepts papers containing faunistic information about birds. This includes descriptions of distribution, behaviour, breeding, foraging, food, movement, measurements, habitat and plumage. It will also consider for publication a variety of oth relevant ornithological material: reports of projects and conferences, annotated checklists for a site or region, specialist other interesting or relevant material.
2017
Concentrations of Palaearctic passerines were discovered at the lights of Ngulia Lodge, Tsavo West National Park, Kenya, in December 1969. It was established that such 'falls' of southbound migrants occurred regularly each November and December when there was low mist or rain at night under moonless conditions. They involved three main species, Marsh Warbler Acrocephalus palustris, Thrush Nightingale Luscinia luscinia and Common Whitethroat Sylvia communis, as well as several other migrants not known west of the Kenya highlands, but included surprisingly few Afrotropical birds. Thousands of migrants were often grounded at night, but these moved on within one day. Such concentrations were rare in spring because of a lack of night mist, but a few April falls revealed a very different species composition. From 1972 to 1992 migrants were ringed by small teams each year over November-December new moon periods. Birds were trapped at dawn in mist-nets set in bush south of the Lodge and, from 1976, in one to three nets set below the floodlights at night. In more recent years larger teams have been involved. Dawn operations were moved in 1994 to an area north of the Lodge, beyond the floodlights, resulting in larger catches, often of well over 1000 birds. Experiment at night with playback of recorded song showed some species to be responsive when already brought low by lights and cloud, but overflying migrants did not react and come to ground on clear nights.