The New Year at Technopole

A pleasure of Technopole for Dakar birdwatching is the easily visible, sometimes unpredictable change in birds. Some of this is seasonal, with regional and continental migration, but I suspect there is also a lot of local movement of birds between here, the other nearby lakes of the Niayes and the coast. The first visit of the year on 8 January also produced four puzzles.

First winter (brown on wings and back) and second winter (no brown), i.e. 6 months and 18 months  age Audouin’s gulls

The same group of Audouni’s gulls.

On our last visit all the gulls were inter-African migrants. Today, they were all of European or at least Mediterranean origin; several hundred lesser black-backed and black-headed gulls and 40+ Audouin’s gulls. The Audouins were a mix of ages, though mostly first and second calendar year birds, with only one adult. The preponderance of young birds around Dakar is also noted by observers at the seawatching point of Ile de Ngor, whilst adults dominate the large roost at Palmarin, 100km to the south. This split of age classes is a mystery.

Black-tailed godwits

Amongst the usual wader species five avocet were new and c350 black-tailed godwit was a good count. The godwits were ignoring the water and feeding on short, dry grassland. The current knowledge is that most of the godwits wintering along the West African coast, mainly Dutch breeders, move rapidly to the rice fields of Casamance and Guinea Bissau and remain there until moving back to the Netherlands via the Iberian peninsula rice fields, so it is interesting to find hundreds in Dakar in January, not feeding on rice grains. Interest in the species has grown recently due to its population decline and classification as globally Near Threatened.

Southern grey shrike

The Technopole list increased to 164 with three not very surprising additions; woodchat shrike, chiffchaff and redstart. More interesting was this lovely southern grey shrike. This is a species that is probably being seen more often south of 15 degrees north than formerly in Senegal – Morel has only two records up to 1980 from these latitudes, when it was frequent further north. From the limited literature to hand here, it is difficult give this bird a sub-specific identification. Three sub-species breed in Mauritania. Senegal birds are assumed or known to be elegans of the central and northern Sahara. Our bird would fit this with the lack of a strong white line above the black mask (white is confined to a small eyebrow), but not with elegans’ pure white underparts. This bird is grey at least on the side and the white eyebrow is not a feature visible in the field. This would point to algeriensis, the breeding species of NW Africa down to coastal NW Mauritania, not yet recorded in Senegal. This will need further checking!

Southern grey shrike. The same  bird, with the sun making the grey underside less obvious.

Puzzle four was what hundreds (low thousands?) of yellow wagtails had found to eat. The very bad photo (mine) shows birds perched in bushes of Prosopis juliflora.

Yellow wagtails in Prosopis juliflora bushes

This small tree is itself interesting. It is related to acacias, but native to Mexico and further south in the New World. It is a popular, but sometimes invasive introduction to poor soils in the Sahel across to Ethiopia, with a large scientific literature on its usefulness. At Technopole, with no livestock to eat the pods, which look like green beans, it just seems to be ornamental. It had a huge number of flies, whilst most of Technopole lacked flying insects. The wagtails were feeding on, and in aerial capture from, the bushes, the leaves of which were covered with their droppings.

Paul

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