Sunday, 26 February 2012

Robins & Blue Tits

I thought I had a pair of Robins and recently a third appeared resulting in much posturing and the occasional fight however a friend, Brenda Cook who holds a licence for bird ringing, visited this last week and in a couple of days had ringed 6 Robins in my garden. This morning, over breakfast I observed another two Robins both were without rings so it seems that at least 8 Robins visit the garden. Have to say I find it rather confusing as I had always understood that by now territories would have been firmly established, perhaps the garden is on the corner of four territories!

Last November Brenda ringed 73 Blue Tits and during this last week a further 70 were ringed plus several birds ringed last year were re-trapped which is good news that they have survived the winter. I am astounded at the numbers of Blue Tits for again, over breakfast watching the feeder through binoculars I reckon that only 1 in 8 Blue Tits had a ring. Knowing nothing about statistics and probabilities but still able to do multiplication that would indicate a population of over 1,000 Blue Tits pass through the garden in Blaenpennal during the day. If this is the case then it would explain why my store of sunflower seeds is diminishing so rapidly!

These two examples suggest that the data I put in for the recent Garden Bird Watch may be somewhat understated so I leave it to the statisticians to work their magic!

Alan Lyne