Some Information Regarding House Crows in East Africa

As you will have read in the most recent blog post (see Pemba post below) recently we saw three House Crows at Wete harbour on Pemba. They were here once before, having spread from Zanzibar, but thankfully were eliminated before they became too numerous. Now they are back. House Crows are extremely intelligent beings, they travel far - often hitching rides on ships, and they multiply rapidly in any area with a dense human population. They expertly exploit all manner of food sources especially in cities, from e.g. the vicinity of schools and playgrounds to any discarded edible material and 'municipal efluvia'!

Notoriously they also persecute indigenous vertebrate species - robbing nests, eating their eggs and/or young.

This presence of House Crows on Pemba is therefore likely to be a further,and very great, threat to the fragile endemic fauna of Pemba.

They were first introduced to East Africa from India by British civil servants in the late nineteenth century. Now they are a major problem in coastal urban areas and are slowly but surely spreading inland along the major roads; as did the House Sparrow, which similarly came originally from India and is now established in country towns and in game lodges, even in remote areas such as the eastern and northern Serengeti e.g. at Lobo Lodge and Klein's Camp.

The rest of this post is comprised of clips from email conversations.

1) In April 2007 Dodoma,
Two days after I saw four house crows at Dodoma airport the airport authorities decided to get rid of all the crows (mostly pied) at the airport. This is a regular excercise, about once a year. They seem to get help from the locust control people from Kenya who base themselves here to spray Quelea. So for a few days there were dead pied crows falling out of the trees around the airport, and there was not a single crow left. I am pretty sure the 4 house crows also perished. Luckily the first pied crows are already returning to the field. Kees Barendse

2) July 2007. I was wondering whether you have seen any House Crows on Pemba Island. I have been tracking their colonisation around the world and my information for Pemba is that they were reported from there in the early 1960s but have not been recorded since. Colin Ryall

3) August 2007. Never seen one in three years in Pemba and was looking out for them! Am in Unguja now and have ONLY seen Indian House Crows. Julia Bishop

4) September 2007. Thank you for the information. This is good news - lets hope it stays that way. As you say, a healthy Pied Crow population is a good indicator too, especially near human population. Colin

5) When working in Zanzibar we used to hear a story of how they were introduced by an Indian sect who do not bury their dead, but leave the bodies out for the crows. Because the local birds weren't into that diet these people imported Indian crows. Do you know if that is true? Lars

6) I might be able to help with Lars's enquiry. I have heard something similar and in fact mentioned it in an article in Swara in 1987. There seems to be a conflation between two different facts here. The first thing is that House Crows were introduced to Zanzibar by two British civil servants in the 1890s. The second is that the Parsee community in India, originally from Persia (Iran) are Zoroastrian, which is much more ancient than the not Muslim religion; they traditionally put out their dead to be devoured by carrion eating birds - vultures and house crows. I doubt this has ever actually been practiced in East Africa. It is an embarassing fact that the British colonials released them at various places - they had the idea that they would keep the streets clean. I would be very interested to hear anything about Persian or Zanzibari attitudes or other info. Colin

7) I knew a few Parsees during my Indian years (1980-82). The problem of disposal has been greatly exacerbated in South Asia of late as the vulture populations have plummeted in the wake of diclofenac and the chemical-industrialization of India's dairy herds. Any ideas for solving the Pemba crow situation? We are now awash with guns it seems, mostly coming from Kenya! Target practice for police marksmen as in Seychelles and elsewhere? James

8) Yes I have read about the problems of corpse disposal for Bombay Parsees since the near extinction of vultures due to Diclofenac. There are captive breeding programmes but it will be a long time - too long I expect before the vulture numbers build up again. If the number of House Crows on Pemba is small the best approach would be shooting but it needs to be carefully done - not a free for all - because then they will just disperse - like they did on Mahe, Seychelles in the late 1980s. Actually, the best thing would be to contact Tony Archer, he is the local expert. Colin Ryall

9) If House Crows did clear-up all the Zanzibar rubbish we would probably tolerate them..in fact they might get an official government department all to themselves. James - how about putting a bounty on their heads in Pemba? At 50shs each I am sure the kids would happily use their slingshots..though it would have to be properly managed. Does that sort of thing tend to work? Has it been done before do you know? Julia Bishop

10) Please could we have some official Govt support for eradicating these crows on Pemba. Just tell these people what you need to do the job. Give them the budget. If it is so few crows (what about HC s at Chake Chake?) then it should be possible to shoot them at the roost. If not then Nnytti might be about to assist with sumu [poison]. If you cannot assist I need to know so I can advise them on trap design and they can talk to officials in Pemba. Who should they talk to on Pemba; who is the most senior person on the island in your ministry? Many thanks, meanwhile I'll dig out some old refs for those interested in the origins of these birds on the islands. Neil Baker

11) I would strongly advise against a bounty because if there is a free for all the crows will be come so panicky you won't be able to shoot them, trap them or poison them. In any case bounty systems may keep the numbers down, but they also guarantee their continued survival. What we need in this case is eradication - while it is possible. We used a bounty system it in Mombasa in the late 1980s but only because eradication was out of the question. Colin

12) My father has added this comment: The crows in Mombasa were allegedly introduced by a couple of Scots in the 1890's. The Secretary of Mombasa Club announced this at an AGM several years ago, and made all the Scots present stand up! Thanks for your comments advising against a bounty Colin, hope that eradication will work then. Julia.

13) Their names were Dr Charlesworth and Sir Gerald Portal - but I didn't know they were Scots - thanks to your father that's a little more info to the story. I wrote about it in SWARA in Jan/Feb 1987 in fact. Colin