Wednesday, 19 June 2013

Life without death in the life of birds.

During Springwatch 2013 there has, once again, been death of young nestling's. This happens every year and every year the presenters Chris Packham, Michaela Strachan and Martin Hughes-Games expertly put the viewers at ease by explaining why it happens and that it is all part of the circle of life. In this blog I will attempt to put this phrase, 'the circle of life' into numbers. Without death in the life of birds the world would become over run.

So lets start with some commoner birds. Currently the Blue Tit breeding population is about 3.3 million individuals. In each brood there are 8-10 eggs laid, so for purposes of this blog an average of 9 eggs laid. We must assume that this is 5 chicks per adult (CPA). Now, without predation or egg failure and assuming all of these chicks survive and are successful and every Blue Tit individual survives then the population would go from 3.3 million to 16.5 million in one year and that's not even considering second broods! In two years time assuming every Blue Tit from the year before breeds, the population would have gone up to 82.5 million Blue Tit's. It is unimaginable to think what it would be like.

Moving onto another common garden bird, Robins. The current population of individuals is 5.5 million. There  are 4-5 eggs laid, so lets say there are 5 eggs laid in each brood. We again, must assume that this is 3 CPA. The same rules apply as did for the Blue Tits, none of the chicks are predated or die from the cold or anything - They all survive. In a single year the population would go from 5.5 million individuals to 16.5 million. An increase of 11 million. The next year it will increase by 33 million to 49.5 million birds. Within two years of this 'world without death' the one Robin that hops around you while you dig will become 5 Robins or 10 Robins.

So you get the general idea that without death bird numbers would, obviously, increase dramatically. But to put this into perspective we need to think about those rarer birds, the ones you really want to see. Now of course we want to see our rarer, less seen birds increase but would this new world prove to much. Well let's take a look at the numbers.
Hawfinches. A fantastically powerful and beautiful bird. Everyone would like to see one but its not that easy with only 9600 individuals breeding in Britain. However, I'm sure you've guessed it, every single Hawfinch is successful, every chick juvenile and adult survive. The population is going to rise rapidly. Hawfinches have 4-5 eggs in a brood, so we will assume they have 5 - 3 CPA. the population will go from 9,600 to 28800 in one year, the next the population will be 86400 . In less than 4 years time Hawfinches will be as common as Robins are today. Imagine that while walking to the Bus station, or the shops and this wonderful powerful Hawfinch dives across you into the bush. Magnificent! -to a point. This would become such a regular occurrence that this wouldn't come into my mind it would be something more like " ooh what's that, oh it's only a Hawfinch." Now I'm not saying that I don't appreciate common birds because I do but the excitement isn't there when you see a common bird and that's what you expect when you see a bird like a Hawfinch.

Well there you have it, should predation and death stop completely then birding just wouldn't give you the same thrill it does today. This is, unfortunately, why we must accept what goes on during these programs. It's a fact of life and without it life would be considerably more boring. So go on, what are waiting for, go and find a rare bird and most importantly - Enjoy it! Happy Birding.

Monday, 1 April 2013

March Review

So here I am once again at the end of a long month of patching wondering what I can write for a 'review' of the month. Last month I didn't consider it necessary to write a review as the review would have consisted of something along the lines of; I saw a Grey Heron, that was it. By the end of February I had 29 species and points, having started the month with 28 species and points (part of the patchwork challenge). This month I fared slightly better finishing on a total of 34 species and points.

I saw 5 new species on my patch this month. This was below expectation however with the cold weather what to expect couldn't be predicted. Anything could have turned up from summer passerines to wintering wildfowl. I had hoped for a few migrants but that will have to wait for April.

So what was the highlight species out of the 5 I saw. It would definitely have to be the flock of 20 Greylag Geese that flew over my patch at dusk. I have a vague idea of the species that I should be seeing over the course of the year and Greylag Geese, or any Geese, was not included in this superficial list. I was so surprised to first hear them calling and then to see them fly over my head. It is moments like those that keep me coming back to my patch.

To conclude, March has be a fine month in terms of seeing species with 5 new species. The birds have began to sing and spring is still attempting to run its course despite the bitter temperatures. I am beginning to wonder if I will ever get any rarities along my patch. Hopefully the spring migration will bring some!

Friday, 22 February 2013

January Review

Now I know it's seems strange to name a blog 'January Review' half way through February but I thought I should 'review' the goings on, on my patch, in January.

My patch isn't known for its rarities, to be brutally honest it isn't known for having any birdlife what so ever. But results from January suggest otherwise. Perhaps not rarities, but certainly a flourishing bird population. Having enthusiastically taken up the job (not a real job!) of surveying a half mile stretch of a small stream in June, it had taken a back seat for the last few months, however I now visit at least 2 times a week fitting it in around various bits of dreaded maths homework.

So to the review. January was quite compared to other patches but 27 species and points was a good start to my target of 50 species on my patch. This may seem pessimistic however it is realistic. On the 1st there were the usuals of Wood Pigeon, Blackbird, Robin and Jackdaw. A few good spots on the 1st were Goldcrest and Sparrowhawk. I had 16 species after my first visit but I did not get my 17th species till the 17th of January. It was a Raven, only identified by its characteristic 'squawk'. My two favourite sightings of January were definitely the Fieldfares who came when the snow came and 4 Mistle Thrushes who I hope may breed this spring. Both of these birds were lifers so seeing them on my patch was even more special.