In A Shrinking Bubble

4 December 2013

As things stand now this intelligent, resourceful, omnivorous bird may go extinct in this century.  Why?  Because he lives in a shrinking bubble.

For a long time scientists could not figure out why Stresemann’s bush-crow (Zavattariornis stresemanni) lived in only one 6,000 square mile area of southern Ethiopia.   He’s really smart, eats anything, and nests cooperatively but the bush-crow does not expand his range even though the habitat bordering his domain appears to be exactly the same.

His size and threatened lifestyle resemble that of the Florida scrub-jay whose range was 7,000 square miles but areas of suitable habitat much smaller.  Scientists approached the bush-crow with the same tools they used on the scrub-jay and came up empty.  The bush-crow’s bordering habitat was the same.  Why didn’t the bush-crow use it?

Then in 2012 a team headed by Dr Paul Donald of the RSPB figured out that Stresemann’s bush-crow lives in a cool, dry climate bubble where the average temperature is less than 20oC (68oF).  Outside his range it’s hotter and he won’t go there.  Terrain and elevation created his zone but climate change is raising the temperature. The bush-crow’s bubble is shrinking and he is Endangered.

If his problem was caused by loss of habitat, as it is for the Florida scrub-jay, laws and habitat restoration could increase the bush-crow’s available land but climate change is a much thornier problem requiring international political will.

Right now there are about 9,000 breeding pairs of Stresemann’s bush-crows on earth.  But for how long?

Click here to read about Stresemann’s bush-crow’s climate preference.  Click here for his range map.

(photo from Wikimedia Commons. Click on the image to see the original)

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