Bonxies and Bee-eaters

This week saw the arrival of the first Bee-eaters (Merops apiaster) of the season. I cannot write about the arrival of these colourful birds without making reference to Howard Irby. He was an ornithologist who wrote a wonderful “Ornithology of the Straits of Gibraltar” in 1875, with a lavish second edition twenty years later, graced by Thorburn’s watercolours. Irby was meticulous in recording bird observations and this is what he said about Bee-eaters arriving across the Strait almost 160 years ago: “My dates of their first arrival are: the 7th April, 1868; 4th of April, 1870; 29th March, 1871; 26th March, 1872; 28th March, 1874; 29th March, 1876; 28th March, 1877; 29th March, 1894.” These dates seem slightly later than today, by about a week or ten days, which makes us wonder if the arrival dates have been really pushed forward by milder springs.

Regarding the numbers passing, Irby tells us that “They were observed passing in great numbers from the 10th to the 14th of April in three consecutive years, the greatest quantity arriving on the 10th; so, in Spanish fashion, I christened that date ‘St. Bee-eater’s day’.” So, we’re gearing ourselves up for this year’s St. Bee-eater’s day! I’m only posting a photo of them today as I will have more to say on these lovely birds in weeks to come.

In the same way that some species seem to have changed their timing of migration, sadly others seem to have declined severely in recent years. A feature of the seabird movements at this time of the year, and throughout the winter, were Bonxies (Great Skuas, Stercorarius skua). Now, we hardly see one. I visited the main breeding colonies on Shetland last year and their numbers were very noticeably down compared to a visit ten years earlier. The reason: Bonxie numbers have been severely affected by Highly Pathogenic Avian Influenza (HPAI or bird flu). The large colony at Hermaness (Unst, Shetland), which had been estimated at 955 breeding pairs in 2018 (roughly 6% of the world population in a single site), had been reduced to 208 in 2023 (a 78% decrease) and 220 in 2024, showing a very slow recovery. A similar decline was reported from Noss (Shetland), from 476 pairs in 2018 to 69 in 2023 (86% loss), with a slow recovery to 80 pairs in 2024.

Adult Bonxies from Shetland are known to winter mainly off north-west Africa and the Iberian Peninsula, fewer in the Bay of Biscay. Unsurprisingly then, numbers down here have declined dramatically in recent years as the numbers reflect the huge decline in the Shetland population. Icelandic birds winter further north than Shetland birds, off Newfoundland, south-west England and Bay of Biscay and the mid-Atlantic. Norwegian birds are similar to Icelandic ones but are more strongly represented in the East Atlantic than Icelandic ones. Birds enter the Mediterranean via the Strait of Gibraltar and a small number reach down the coast of West Africa. Adults travel shorter distances than immature birds, which wander over greater distances.

We now have to wait and see how the Shetland population recovers and see if more birds start reaching us in winters to come. Like with Irby’s records of Bee-eaters, we see the value of meticulous and systematic observations. It’s the only way to get a handle on changing population numbers and migration patterns.