14 February 2011

Painted Reed Frogs

I probably spend a bit too much time around my little fish pond. I ignore the Raucus Toads (too noisy) and keep an eye on the Painted Reed Frogs.

At night it is all sex and music. The adults sit on the lily pads and surrounding vegetation and make their not unpleasant “short, high pitched, explosive whipp-whipp whistles, repeated once every second.”* They do this in a massed choir and it certainly works well for them and there are many happy couples clasping each other in the water and tadpoles in the pond. So many in fact that we have a new visitor, a Fishing Spider, that is providing a bit of tadpole population control.

It is not what happens at night that has caught my attention, it is how the frogs disperse during the day that I find fascinating. The total population of Reed Frogs is about 20. During the day there are at most 4 around the pond and the rest go and hide in the garden. I find their choice of hiding places interesting.

It makes good sense for a young frog to spend the day in the rain gauge. A frog would want to know if there was rain as it would enhance the night’s activities if there was more water – although the only time they go into the water is to escape predators or mate. Completely inexplicable is one frog (I call him Herbert the Invisible) who sits in full sunlight in the middle of a brick wall in full view of all predators (who range from birds to snakes). He (or she) persisted in doing this and eventually there were 3 “invisible” wall sitting frogs. One brave frog sat in an aloe for about 3 weeks, every day on the same sharp and thorny leaf. His bright colours made him stand out against the dark leaf. Again it did not really make sense.

Stranger still are the Painted Reed Frogs who like the pink or orange buoys. We live near the sea and cannot leave a buoy lying on the beach and the garden is full of them. They ignore most colours and if you really need a frog looking in the pink buoy is almost guaranteed to be successful. They don’t like yellow or red and tend to ignore all the other buoys.

My favourites though are the frogs who spend the day waiting for the night’s action on the pond as I don’t have to spend too much time looking for them. There is always one boring one who will spend the day sitting on a lily pad but then there are the ones who sit on the lily flowers. Some spend the day on the flower stalk, probably convinced that they are invisible. The really fascinating ones sit inside the flowers or on the petals. During the peak sunlight hours the flowers are completely open and as the light starts fading the flowers close and the frog travels on the petal till he or she is completely enclosed by the flower.

I am no scientist and cannot really explain their choice of daytime resting spots. I do know that they do not like being disturbed and if you do so the frog will choose another spot to spend the next day. Maybe I should spend more time doing some real work…..

du Preez, L and Carruthers, V. A Complete Guide to the Frogs of Southern Africa. Random House; 2009.

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