Impacts of Rhodes on Biodiversity 2 : Common Chaffinch

21 records of Common Chaffinch in BirdPix

The first blog in this series talked a bit about Cecil John Rhodes and his beliefs, which can can be summarized in this quote: “Remember that you are an Englishman, and have consequently won first prize in the lottery of life.” The first blog in the series actually focused on Eastern Grey Squirrels, introduced by Rhodes to his estate in Cape Town about 1900.

This blog focuses on four of the five bird species which Rhodes introduced around 1900. Three of the four went extinct fairly fast. After 120 years, the fourth is hanging on.

We can dismiss the first three species in a couple of paragraphs: Rook Corvus frugilegus, Song Thrush Turdus philomelos and Common Blackbird Turdus merula. The Atlas of the Birds of the Southwestern Cape says that Rhodes’s consignment of about 200 Rooks lasted only two years:

The species account for the Rook in the Atlas of the Birds of the Southwestern Cape, published by the Cape Bird Club in 1989

So one sentence was enough to deal with the Rook. The Song Thrush was “still holding its own in the gardens of Newlands” in 1937, but within 10 years it was extinct. So it lasted about four decades. The Song Thrush has also been introduced to New Zealand, where it are common, and to Australia, where it occurs mainly in Victoria and New South Wales. There were a few Common Blackbirds in and around Cape Town until about 1930, so they lasted about three decades. The Common Blackbird was also introduced to New Zealand, where it became one of the most widespread bird species, and to Australia, where the Atlas of Living Australia has more than 352,000 records of the species, mainly from Tasmania, Victoria, New South Wales and South Australia. It is a puzzle that Song Thrushes and Common Blackbirds did not become established here in the same way as they succeeded in similar climates in Australia.

From the Presidential Address of Dr R Bigalke, entitled “The naturalisation of animals, with species reference to South Africa“, and published in the South African Journal of Science in 1937

The fourth of the four bird species considered in this blog is the Common Chaffinch Fringilla coelebs. 120 years after it was introduced it has neither gone extinct, nor has it taken off. In his 1937 Presidential Address, Dr Bigalke also wrote:

So, in about 40 years, the Chaffinch had spread about 5 km to the south, to Wynberg, and presumably around the northern end of Table Mountain, via the City Bowl to Camps Bay, a distance of about 10 km via Kloof Nek. 50 years later, in the Atlas of the Birds of the Southwestern Cape, published 1989, with fieldwork 1981 to 1985, the species account for the Chaffinch reads like this:

… A female was seen at Klaasjagersberg in the Cape of Good Hope Nature Reserve.

So, between the 1930s and the 1980s, the range did not change a great deal. It was still unable to break out of the Cape Peninsula! Subsequently, with the removal of alien trees from the Table Mountain National Park, the range of the Chaffinch has possibly contracted.

At the moment, August 2020, there are 21 records of Common Chaffinch in BirdPix. Here they are:

Thumbnails of the 21 records of Common Chaffinch in BirdPix

If you plot these 21 BirdPix reecords onto a map of the Cape Peninsula, this is what you get:

Working our way from north to south along the eastern edge of mountain chain of the Cape Peninsula, the first BirdPix record was in the parking area at Rhodes Memorial, close to the University of Cape Town. A few kilometres to the south, there is a cluster of seven records in the Kirstenbosch National Botanical Gardens. Then there are scattered records southwards via Constantia to the Tokai Forest, where the Table Mountain National Park has its headquarters. There are four records farther away from the mountain in the suburbs. From north to south: the eastern edge of Rondebosch and Access Park, Kenilworth (these two records are immediately west of the M5 highway), then one in Bergvliet and one in Kirstenhof. Access Park is a “retail precinct”, but hosts a good scattering of pine trees, which are a Chaffinch magnet.

On the western side of the Cape Peninsula mountain chain, Bigalke mentioned Camps Bay and the atlas mentioned Hout Bay. BirdPix has a single record for this side of the Cape Peninsula, from Noordhoek, a few kilometres farther south than the earlier records.

This detailed map of distribution records provides the start of a baseline against which change can be measured. But with only 21 records, it is likely to be incomplete.

Are there still Chaffinches in Camps Bay, or Hout Bay? Are there any in the City Bowl, where there are lots of pine trees? What about Pinelands, a suburb where the stone pines were preserved when the houses were built? If you know of other places in and around Cape Town where Chaffinches occur, please try to get a photo. (This is not an easy task; patience needed.) Please upload your records to the BirdPix section of the Virtual Museum. Old records are also welcome.

This male chaffinch was photographed at Groot Constantia on 28 September 2019. There is a second photograph in the BirdPix database of a female on the same day at the same place. See http://vmus.adu.org.za/?vm=BirdPix-93977

Breeding records!

Off on a different track, it seems that the last record of breeding Chaffinches was made in September 1987. That’s 33 years ago, so it is worth reproducing it in full. The nest was found by David Allan, and he wrote an excellent record of the breeding event. His report is published in Promerops, the newsletter of the Cape Bird Club:

Promerops number 182, page 14, published in February 1988

Chaffinches elsewhere

Common Chaffinches occur as an indigenous species in Europe and eastwards far into Asia. In western Europe they breed from Spain and Portugal in the south to Norway in the north. A few breed in Morocco and Algeria in north Africa, so it can be claimed as an African species. As the distribution extends eastwards into Asia, the latitudinal range gets narrower. The indigenous range is characterized by trees: areas with deciduous forest, coniferous forest, or mixed forest of both deciduous and coniferous trees.

Rhodes was not alone in wanting to make the countries they had moved to, with their strange and unfamiliar biodiversity, look and feel and sound like “home”. The earliest “bird clubs” were known as “acclimatization societies“, and their objective was to bring consignments of birds from the “home country” and release them in the “new country”. The most successful acclimatization societies were in New Zealand. The list of British bird species they introduced to New Zealand is impressive. The Chaffinch is one. Several hundred were released in Auckland between 1864 and 1869, and there were similar-sized releases in towns and cities in both the North and South Islands. Chaffinches “acclimatized” slowly in New Zealand (see here), but within five decades they had overrun the country, and even expanded into the natural forests. In contrast, the acclimatization societies of Australia and North America had total failures with the Chaffinch.

Three things can happen …

The Common Chaffinch in the Cape Peninsula is a rare example of an introduction that has neither taken off nor gone extinct. Three things can happen. 1). They can bumble along indefinitely, in the way that they have done for the past 120 years. 2). They can follow the Rook, the Song Thrush and the Common Blackbird and go extinct. 3). They can all of a sudden discover the elusive secret of success, and suddenly become an invasive species. Number 3 happened in New Zealand, and Number 2 in Australia and North America. We have no idea! But what we, as citizen scientists, can do is to monitor the population carefully.

The final blog in this series will deal with Rhodes’s big “success” story, the Common Starling Sturnus vulgaris. If his vision of building a railway line northwards from Cape Town through Africa to Cairo failed, his starling has made a modest start in covering the distance!

Acknowledgements

Itxaso Quintana produced the map. Thanks to everyone who submitted records of Chaffinches to BirdPix.

Les Underhill
Les Underhill
Prof Les Underhill has been Director of the Animal Demography Unit (ADU) at the University of Cape Town since it started in 1991. Although citizen science in biology is Les’s passion, his academic background is in mathematical statistics. He was awarded his PhD in abstract multivariate analyses in 1973 at UCT and what he likes to say about his PhD is that he solved a problem that no one has ever had. He soon grasped that this was not the field to which he wanted to devote his life, so he retrained himself as an applied statistician, solving real-world problems.