Indian house crows and their eradication from Mahe |12 October 2009

Apparently, sailors feed and encourage them to remain on board.

It is highly likely, therefore, that individuals have been introduced to Seychelles via Indian cargo ships.

According to historical records, there was a small population of about 30 korbo around the north-eastern region of Mahe during the early 1980s, probably established after “jumping ship” during the 1977 invasion.

Being opportunistic scavengers, they often out-compete other avian species throughout their Asian range and, historically, a local presence had coincided with a decrease in poultry production.

The crows were often observed feeding on discarded waste and in gutters, raising concern about the probability of their spreading diseases to native avian species or even human beings.

Recent observations have shown their preference for smaller native vertebrates, particularly endemic geckoes and skinks, which suggests apparent competition for prey with the Seychelles kestrel (Falco araea).

The korbo is thus considered a pest and a devastating predator wherever it has been introduced.

The small population was eradicated in 1994 after a R500 bounty was introduced in 1992 to promote public involvement. According to records, the first bounty for a dead crow was paid on March 5 1992.

With increasing movements of cargo vessels between Asia and Port Victoria, lone individuals were observed and shot during 1998, 2002 and 2005. During May 2009 a lone individual was sighted and reported on Mahe, and after nearly two months of intensive monitoring and searching, the korbo was shot.

Around mid-July, another lone individual was reported. Following an awareness campaign, reports from the public and localised
observations, behavioural patterns and movements were determined and became predictable.
 
That crow, however, proved to be as wary as previous ones. It took nearly two and a half months to lure it to a feeding station high up in a Ficus nautarum tree, where it was shot – another victim of our sharpshooter Sergeant William Magnan of the Public Security Support Wing (PSSW), formerly SSU (Special Support Unit).

An analysis of crow occurrences on Mahe would reveal a considerable amount of man-hours and financial resources invested by the government as preventive measures against the korbo as a potentially detrimental species.

Accidental introduction remains random, cannot be prevented and may be difficult to control; investment to eradicate invasive alien species is unavoidable because it signifies a commitment toward conserving Seychelles’ biodiversity.

The Department of Environment extends its gratitude to members of the public and stakeholders who continue to prove that they are of great help in its endeavours to achieve control over invasive alien species in Seychelles. 

The department continues to rely on your valuable information, concerns and collaboration.

Please call the Greenline on 722111 if you have any environmental concerns to report.

Department of Environment (Ministry of Environment, Natural Resources and Transport)