The local Blue Swallow, Hirundo atrocaerulea, population is facing the risk of certain extinction if both their breeding and non-breeding habitats cannot be urgently secured. The Endangered Wildlife Trust's (EWT) Threatened Grassland Species Programme has started monitoring the breeding population as part of a long-term project. Long-term monitoring is essential to determine population trends and provide valuable information to conservation authorities ito inform grassland management decisions.
According to Dr. Ian Little, programme manager of the EWT's Threatened Grassland Species Programme, "Loss of suitable habitat is the primary cause of the blue swallow's population decline, however causes for recent continued declines are uncertain.
Four known regional populations of the blue swallow have already gone extinct in South Africa in the past decade. This includes a breeding population that was in the Kaapsehoop region, which was once recognised as a blue swallow natural heritage site."
The South African population currently consists of fewer than 38 known breeding pairs, with less than five remaining in Mpumalanga and 35 in KwaZulu-Natal.
These alarming numbers resulted in the South African population of this small bird being listed in the Eskom Red Data Book of Birds of South Africa, Lesotho and Swaziland as Critically Endangered. The population has continued to decline since this listing was recorded. The total global population is thought to number about 1000 breeding pairs, but the data is under review by the newly instated International Blue Swallow Working Group.
Little and his team have discovered that the number of breeding pairs continues to decline regardless of how many fledglings are produced each year.
"We currently have no idea as to the survival rate of these fledglings. To gain a better understanding of the mortality rates of these birds we have begun to conduct research utilising microchip technology.
We started PIT-tagging the fledglings in November 2011. PIT-tags – or Passive Integrated Transponders – allow us to monitor the juvenile survival rate and reproductive success, among other important conservation related questions, of the birds.
We will only start receiving results when the birds return from their winter migration next summer."