Summer migrants and vagrants
The exceptional rains brought several feathery vagrants to Tswalu this season. If you think about it, birds are the only group of animals that still have complete freedom of movement. They cannot be contained, like other animals, as a result of fence lines and other barriers that restrict natural movement or migration. While migrant birds are common on the reserve, vagrant birds are a fascinating phenomenon. Vagrants, defined as migrants found outside of their normal range, sparked my curiosity more than ever this summer.
Below are 10 of the surprise bird sightings I recorded, and some thoughts on why their presence was unusual.
Red phalarope (Phalaropus fulicarius)
This marine wader is a summer migrant rarely seen inland. I was lucky enough to spot it paddling around in a rain-filled pan, dipping its head and feeding on zooplankton.
Lesser Moorhen (Paragallinula angulata)
Far from its normal range, this moorhen stayed on the reserve for over a week, most likely moving off because of a lack of potential mates.
Western osprey (Pandion haliaetus)
This fish-eating bird of prey was way out of its normal distribution area. Ospreys feed almost exclusively on fish, of which there are none on Tswalu. It was seen for one day before it probably moved on to better hunting grounds.
Grey-headed Kingfisher (Halcyon leucocephala)
With its sapphire blue tail and flight feathers and vermillion bill, this kingfisher stood out! Again, it was very far from its normal range and also didn’t stick around for very long, probably for the same reason as the moorhen.
White-winged Tern (Chlidonias leucopterus)
Generally found in or near bodies of fresh water, including wetlands, this sighting was less of a surprise as its distribution is closer to Tswalu than the other vagrants on this list. Terns feed mainly on fish, aquatic invertebrates and small crabs – not characteristic of Tswalu.
Greater Painted-Snipe (Rostratula benghalensis)
An omnivorous wader favouring grassy fields and marshes, its range limits are quite far from Tswalu. Two individuals were seen on the reserve over a period of almost a month.
Dwarf Bittern (Ixobrychus sturmii)
Like most herons, this wader is usually found in densely vegetated wetland habitats, and was a few hundred kilometres from its normal range. As it feeds mainly on frogs, fish and aquatic insects, the three individuals identified on the reserve were most likely feeding on the froglets and tadpoles that were abundant after persistent rain.
African Spoonbill (Platalea alba)
A long-legged wader with a distribution range limit fairly close to Tswalu, several individuals were seen throughout the summer. In the absence of fish, they were probably feeding on aquatic invertebrates especially at the beginning of the rainy season.
Hamerkop (Scopus umbretta)
Only one individual was seen over the course of two days, feeding on its main food source of froglets. Though Tswalu is included in the hamerkop’s distribution range, it is certainly not a bird we see often.
Egyptian Goose (Alopochen aegyptiaca)
Populations of this waterbird exploded this summer, displacing other water bird species that used to be seen on the reserve, such as the South African Shelduck. Whether the influx of Egyptian geese is as a result of their natural expansion as a species, or the rains, remains unclear.
Images by Barry Peiser.