19 August 2008

The Sounds of the Bats

The comforting sounds of the fruit bats (Eidolon helvum) squabbling as they sort out their sleeping quarters for the day is a familiar sound to anyone living in this part of the world. All night these bats have been foraging throughout the country side looking for ripe bananas, mangoes, papayas, guavas, baobab flowers and numerous other sweet meats and flowers from which they gain the needed energy for another day of hanging upside-down in the trees that populate the Bouaké campus. Because of the disappearance of many of the forests around Bouaké these creatures find the campus more attractive than ever before.

They begin to pick out their roosting sites at about 4h30 and continue until 6h00 or so when the sun begins to show its light. This provides for quite the chorus as they all try to get into the right spot for the day where they will be well hidden and with the right companions. In the process males call out to make sure that they attract the right females with whom they will do so specialized “squabbling” in an effort to make sure that the trees remain full of fruit bats.

This noise that we old timers find so comforting and familiar is one which creates quite the stir for any newcomer. It has been described as similar to that of a small hammer hitting the side of a steel hulled sunken ship. Having never hit the side of a sunken steel hulled ship while under water, this is difficult to verify that this is actually the case although it does provide for an interesting image. If you think about it in these terms however, you could get the impression that you are a fish at 5h00 in the morning until you hear the muezzin call for prayer!

Fruit bats may be seen by the thousands in the old kapok tree groves on the Plateau in the city of Abidjan. At dusk in Abidjan if one looks to the sky these bats can be seen flying off out to the fields where they will feed all night before returning to the center of the largest city in Côte d'Ivoire to spend the day squabbling over roosting spots, mating rights, view points and numerous other seemingly mundane issues, strangely mirroring what is going on in the streets of the city below them. This large population of bats supports a relatively large colony of black kites (Milvus migrans) as well which can often be seen flying among the clouds of bats at dusk as they fly out to their feeding grounds. They can pick out a small and infirmed bat fairly easily, usually avoiding the healthy and bigger bats.

The one drawback of having fruit bats around is that the fruit takes a beating as it is fruit that they eat. It is not uncommon to find that if you want to eat a fresh mango you are going to have to share part of it with a fruit bat. Not that big of a deal unless of course the bat has had the whole night to eat that mango you were waiting to pick when it was just so. Then it can be aggravating. My bet is though, with all of the mangoes our forefathers planted on this campus, it will be a long time before we are forced to share every mango with a bat. Oh yes, we also have a small colony of black kites that have found nesting in our kapok grove a desirable spot for rearing their young and teaching them the delights of fresh fruit bat dinner while on the wing.


Childlife said...

The only occasion I have ever heard the sound of bats of any species described as "comforting" -- leave it to you, Rod! ;D

I suppose I could manage to find the sound comforting in the sense that they are preparing to make themselves scarce for the day... Say 'howdy' to Angelika :)


Dan Buck said...

I spent a year at ICA and remember the loads of luscious mangoes all coming ripe at once. They were more than we could eat.

But I don't remember having to share any of them with fruit bats.

AfriBats said...

Great post! I'd be very interested to hear more about the Eidolon-colony in Bouaké as we're currently mapping major colonies of this species across sub-Saharan Africa.

Thanks, Jakob