Weaver news

Weaver Wednesday 3 [239] - Range changes [2]: White-browed Sparrow-Weaver

2017-01-11 (761)

gravit8 Weaver Wednesday 3: range changes in S Africa (species text)

White-browed Sparrow-Weaver Plocepasser mahali

Read more in Biodiversity Observations.
map
White-browed Sparrow-Weaver, Range-change map between SABAP1 (1987-1991) and SABAP2 (2007-current).
Red, orange and yellow = cells with very large, large, and small relative decreases
Blue, dark green and light green = cells with very large, large and small relative increases.
Cells = quarter-degree grid cells; Only cells with at least 4 checklists in both SABAP1&2 shown. All cells had this species recorded in SABAP1 or in SABAP2 or in both (more about interpretation at Biodiversity Observations 7.62: 1-13).

Range changes in SA

White-browed Sparrow-Weaver
White-browed Sparrow-Weaver,
figure from Birdpix

Range change summary
More 4 lists 30 lists
increases n % n %
Decrease 237 29 46 19
Tiny change 184 22 55 23
Increase 411 49 138 57
Total 832 100 239 100
In South Africa the White-browed Sparrow-Weaver has more grid cells with increases in reporting rate than cells showing decreases, between SABAP1 (1987-1991) and SABAP2 (2007-). The points below match the points on the map above.

1. Population increase in the Eastern Cape
The White-browed Sparrow-Weaver has increased in numbers and range in the Eastern Cape, spreading southwards through the Cradock district since 1950.

2. Historic southern limit
Other than the isolated Eastern Cape population, the southern limit of the White-browed Sparrow-Weaver is about 31S, although the limit of the core (higher reporting rate) is about 30S.

3. Population increase in Kgalagadi Transfrontier Park
The Kgalagadi Transfrontier Park shows large increases between SABAP1 and SABAP2, so that the central core range of the White-browed Sparrow-Weaver appears to extend into the Park.

4. Population increase in the Free State
There are widespread large increases in reporting rate in the Free State (other than the western parts).

5. Population increase in KwaZulu-Natal
There are increases and decreases in reporting rate in localised grids in KwaZulu-Natal - there are also additional published sightings in other parts of the province, showing increasing records, probably due to increasing bush encroachment.

6. Population increase in the Lowveld and Kruger National Park
There are increases in reporting rate in the Lowveld and Kruger National Park - there are also additional published sightings in this region, showing increasing records, probably due to increasing bush encroachment.

Range changes elsewhere

Kenya: increase in numbers in Nairobi (Oschadleus 2014d).