Weaver news

Weaver Wednesday 3 [247] - Range changes [10]: Cape Weaver

2017-03-08 (770)

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

Cape Weaver Ploceus capensis

Cape 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).

Cape Weaver
Cape Weaver,
figure from Birdpix

Range changes in SA

Range change summary
More 4 lists 30 lists
increases n % n %
Decrease 366 35 165 33
Tiny change 298 29 172 35
Increase 364 36 163 32
Total 1028 100 500 100
In South Africa the Cape Weaver has about the same number of grid cells with increases, as cells with decreases, in reporting rate, between SABAP1 (1987-1991) and SABAP2 (2007-).

The points below match the points on the map above.

Areas with very large increases include:
1. Lower Orange River in the Northern Cape.
2. Central parts of the Northern Cape and western Free State - new range records at scattered localities.

Areas with mixed changes:
3. Western Cape - this is the core part of the range for the Cape Weaver, with some grids showing large increases, but most grids showing small changes (either increases or decreases).

Areas with very large decreases:
4. Border of the Western Cape and Eastern Cape.
5. Gauteng - the Cape Weaver occurs here at a low reporting rate.

Range changes elsewhere

Namibia: breeding records on the Namibian side of the Orange River (Oschadleus 2016z3).