|Greater Flamingos, India|
Whatever there food preferences, the diet of flamingos will contain carotenoid pigments derived from blue-green algae, which are the source of the pink or red in their feathers and skin. Different species have different levels of pigment, and deposit them differently in their feathers, which is why different species may vary from almost white to deep red. Young flamingos have feathers which are white or brown, and take at least ay year for the feathers to turn fully pink. The bare parts, especially the legs, can take several years to colour up.
Flamingos are very long lived birds – they have been recorded as living in to their 50’s in captivity and probably often reach at least 30 in the wild. They need a long lifespan as they are not very productive – they only lay a single egg at a time and probably in the wild only raise a youngster to independence perhaps one year in three. They are of course famously social – colonies can reach many tens of thousands of birds in the Rift Valley. Even these vast flocks however may only be a shadow of the numbers that once existed – for example during the Messenian Crisis around 6 million years ago the temporary closure of the Straits of Gibraltar essentially caused the entire Mediterranean to dry out into one giant salt pan, which would have been prime flamingo habitat. The numbers living then must have been truly astronomical. We know that flamingos very similar if not identical to the modern forms were around then from fossils – modern-type flamingos go back at least 30 million years.
As a result of their specialised habitat, flamingos are at risk of human interference. Disturbance, drainage of lakes, and industrial pollution are probably the main threats. Having said that, around the Mediterranean flamingos will often breed and feed close to human activities, especially salt pans. There are major colonies in Spain and the Camargue, and they also winter on Cyprus.
|Chilean flamingos, Norfolk, UK 2010|
At Bristol we had a good breeding season this year, raising seven chicks. This takes our flock to 38 birds, close to the minimum size for regular annual breeding. The youngster can be told by their white plumage and grey legs. Adult males are much taller than females. The captive diet is a specially prepared artificial diet which contains an artificial colour compound to replace the carotene in the wild diet. Flamingos are quite hardy birds, but in severe weather they are shut inside their house.
Well, that’s about all for this week. Next week part one of the review of the year, which has been a significant one for Bristol Zoo and for me.
(Images from wikipedia, Norfolk Wildlife trust website)