by Neil Thomson

I read with interest the article “Barn Swallows wintering in Namibia – is there a substantial decline in the country?” by K-H and CH Loske published in Lanioturdus 57(2).

My gut feeling, after living and birding in Namibia for over forty years, is that we see fewer Barn Swallows now than in years gone by. This is, however, a personal impression and not backed up by any personal data.

I have only once witnessed Barn Swallows descending to a mass roost and that was at Gross Barmen in March 1989 when we saw thousands of birds going down to roost in the reed beds as the sun was setting.

I would, however, like to comment on a few issues in the said article.

The authors mention seeing large numbers of Barn Swallows perching on telephone wires and fences between 02 and 28 March 1984 but seeing virtually none on the roadside wires between 29 January and 13 February 2024. I believe there is a simple explanation for this and it has little to do with the numbers of Barn Swallows in the country. It is my experience that Barn Swallows are observed in numbers perched on telephone wires, power cables, fences and even bushes only in the week or two immediately prior to northward migration. Mid to late March would be the time for this phenomenon and I would not expect to see the birds gathering this way in February. I understand that Barn Swallows in the northern hemisphere are also seen perched in large numbers immediately prior to southward migration.

They also comment on the dearth of Barn Swallows after heavy rain showers in certain areas in 2024. While there were a few localised heavy downpours, 2023/24 was generally a very poor rainy season in Namibia – in Windhoek I measured only 282 mm whereas my average for 37 seasons is 389 mm. As far as I can determine the 1983/84 rainy season was close to average (at least in central Namibia). If birds have some way of sensing where the good rainfall and better food source will be, or, had they arrived, found insufficient food and moved on, the swallows may well have been largely absent from Namibia in the summer of 2023/24.

The authors also mention large concentrations of feeding Common Swifts in the absence of Barn Swallows. I would like to suggest that the swifts are more adaptable and better able to exploit the termite emergences than the swallows. Barn Swallows roost at night and are area bound by suitable roosting sites while Common Swifts remain on the wing and are able to follow the rains and thus exploit the emerging insects in areas without swallows.

I find it unfortunate that the authors did not consult the SABAP2 data in which many of us have invested a great deal of our time. Perusal of the species map for Barn Swallow shows that most Namibian records are in the northern half of Namibia but there are huge gaps in the coverage with the south particularly poorly atlased. It should be pointed out that the SABAP2 data show reporting rates, that is, presence/absence and not numbers present but it stands to reason that birds present in numbers will show a higher reporting rate than uncommon solitary birds which may be difficult to find.

The SABAP1/SABAP2 comparison map shows an increase in the reporting rate in SABAP2 in certain areas particularly central Namibia, the Etosha National Park and surrounds and the Zambezi Region, all of which had relatively low reporting rates in SABAP1. The reporting rate comparative graph for Namibia shows a decline in the

reporting rate since SABAP1. Interestingly, all southern African countries and all South African provinces with the exception of the Western Cape, Eastern Cape and Free State show declines in the reporting rates from SABAP1 to SABAP2. The three provinces showing increases all had relatively low reporting rates in SABAP1.

While not conclusive the above certainly points to a decline in Barn Swallow numbers in Namibia and southern Africa as a whole.