The fires that ravaged the Cape Peninsula last year might be a distant memory for many but they lie at the heart of research by Professor Peter Ryan, who set out to gauge their impact on local birdlife.
Professor Ryan set up a monitoring programme through UCT’s FitzPatrick Institute of African Ornithology to assess how the region’s birds reacted to the fire.
What started as a small fire in Peck’s Valley above his home in Muizenberg on March 1, 2015 burned about 5 000 hectares of fynbos over five days, between Constantia Nek and Fish Hoek valley. Many were worried about the impact the massive fire would have on the area’s animal life.
On Tuesday June 28, Professor Ryan spoke at the Cape Research Centre in Tokai Park. His topic was “The Birds They Are a Changing”, and he reported back on post-fire monitoring of birds in Silvermine following the March fire. He also considered how bird communities had changed on the peninsula over the past four decades.
He said fynbos was not an ideal habitat for bird species, although local birdlife had adapted to cope with sporadic fires and would flee advancing flames to seek refuge in rocky outcrops.
Following a fire, he said there would be an increase in birdlife with some birds moving into the area. Some birds enjoyed fires because they opened up the ground for foraging.
Black-headed herons, pied crows and white-necked ravens patrolled burnt areas searching for fire victims.
Professor Ryan said the group hardest hit post fire had been the nectar-feeders with most orange-breasted and Cape sugarbirds displaced into unburnt areas and the urban fringe. “But they’re doing fine now because plants soon create their food,” he said.
He saw little change among insectivores, a decrease in grassbirds post-fire followed by an increase and then a dramatic decrease. “I don’t know why? Are they dying or moving out,” he said at the talk. Of concern, he said, were the black swifts, which nested on rock faces, and were being disturbed by the chanting and clapping of prayer groups that congregated in the birds’ habitat throughout the night. Generally, he had not seen much change in the number of birds on his mountain route. He would like to see birders who live around the mountain adopting a regular “my bird patch” route, counting birds and adding to research.
Birds on the Cape peninsula
Professor Ryan said the first bird atlas project during the 1980s and 1990s had recorded 312 species from the southern peninsula.
Since the second bird atlas started in the 2000s about 215 species have been recorded. Excluding vagrants, the count in the 1980s was 237 and in the 2000s there were 207, with a total list of 245 species, indicating that some species have disappeared and others have arrived.
New arrivals are easier to detect, and perhaps the most obvious is the hadeda, which reached the Cape about 20 years ago and are now prolific. Another former vagrant to the south peninsula is the pied crow which, back in the 1970s, would have created excitement in the south. The red-eyed dove also arrived, drawn to transformed areas of well-wooded gardens and lawns.
Waterbirds and risks
The biggest changes are with waterbirds, with a few species arriving in the region.
One of them is the goliath heron possibly due to the introduction of carp. However, many more species have disappeared. Hamerkop, which once bred in the area, has disappeared from the peninsula and black storks, which arrived each winter. African rails have disappeared from Zandvlei, and half-collared kingfishers are no longer seen this side of George. An addition we do not want, according to Professor Ryan, are introduced mallards, which hybridise our native ducks.
Bad news is that sanderlings are no more on the peninsula with a 90 percent loss throughout the Western Cape since the 1980s and turnstones are down by 50 percent.
Good news is that African black oystercatcher’s numbers have doubled since the 1980s. This is thanks, in part, to restricting vehicle access to beaches and the accidental introduction of an invasive mussel, which has greatly increased their food.
Professor Ryan said long distance migrants were at risk because they depended on a network of stop-over points on their vast migrations from their breeding sites in the northern tundra. “They stop over on this journey, but are affected when links in the chain are disrupted. Climate change also is affecting their breeding grounds,” he said.
A more local cause for concern is the decline and local extinction of white-fronted plovers. Human disturbance is directly responsible, with many chicks eaten by dogs on beaches. However, some birds are becoming more common on our coastline include Egyptian geese, hadedas and sacred and glossy Ibis. Common swifts were unrecorded until 20 years ago and are now regular visitors.
l If you would like to get involved in adopting a regular “my bird patch” route and counting birds, as this would add to research, visit the Animal Demography Unit websitehttp://mybirdpatch.adu.org.za