"To see a world in a grain of sand,
And a heaven in a wild flower,
Hold infinity in the palm of your hand
And eternity in an hour."

From "Auguries of Innocence"

by William Blake

Saturday, 2 June 2012

A Bird Survey with a Difference

If you watched "BBC Springwatch" last Thursday, the 31st May, you will have seen the launch of a British Trust for Ornithology (BTO) Survey called the "Big Garden Weigh-in". The survey will look at the structure of garden bird communities and how they differ depending on location, size of garden and local habitat. The survey will form part of a large area of research, including the BTO Garden Bird Watch and Garden Bird Feeding Survey, to examine how garden bird communities vary throughout the British Isles in relation to habitat and over a period of time.

The survey will take place between 31st May and 5th June and anyone can participate (just visit www.bto.org for more details). All you need to do is watch your garden and count the maximum number of each of 60 species seen within an hour on one of these days.

After entering your records a bird biomass score for your garden is calculated and then you can find out how this compares with other UK gardens.

Some of the initial findings will be reported on "Springwatch" and eventually a peer-reviewed scientific paper will be prepared for publication.

I watched my garden for an hour today and recorded the birds and here are the results: (you will see the larger the birds are that visit the higher the biomass!). (Although I am not particularly happy at seeing magpies, carrion crows or great spotted woodpeckers in the garden when bird are nesting, I would have liked to see them during this particular hour to boost my garden biomass a bit!)

Feral Pigeon x 2 weighing 289g each = 578g

Wood Pigeon x 4 weighing 403g each = 1,612 g

Blue Tits x 2 weighing 11g each = 22g

Great Tits x 2 weighing 18g each = 36g

Coal Tit x 1 weighing 9g each = 9g

Blackbird x 2 weighing 95g each = 190g

Robin x 2 weighing 18g each = 36g

Dunnocks x 2 weighing 20g each = 40g

House Sparrows x 6 weighing 26g each = 156g

Chaffinches x 2 weighing 21g each = 42g

Greenfinch x 1 weighing 27g each = 27g

Goldfinches x 2 weighing 15g each = 30g

Total biomass of the garden for all bird species = 2,778g.

A nice little bar graph is produced as well showing the above results

Compared to the rest of the UK

my bird biomass at this moment in time is 57th out of 115 bird biomass submissions from the West Midlands region and 731st out of 1,295 submissions from the entire British Isles.

I found the biomass results very interesting and an added bonus was that in watching garden closely for an hour I saw my first house sparrow and great tit fledglings!

If you decide to take part I would love to hear how you get on.


Rohrerbot said...

I like this idea very much. It has been so hot here. I finally broke down and went birding last night. Apparently all the critters feel the same as well because there was so much to see!! BUT I sat by my window yesterday watching all the birds and like you say, you'd rather not have several birds hanging out as much....well I have several as well:) They're all welcome but our Mourning Doves and be a little heavy on the branches:) Sounds like an interesting project.

Ragged Robin said...

Chris - It is an interesting project - I like things like this its fun to do and you can make a tiny contribution to help.

Glad you saw so many birds last night despite the heat. Here its cold and very rainy again! To give you an idea the maximum temperature yesterday was 14.0 degrees centigrade. Apart from tomorrow it looks like its going to rain most days next week too!

Rohrerbot said...

Oh my goodness.....how does anything EVER dry??!! Let me see....in my part of the world, I had another amazing day in the wild during a morning hike BUT a terrible fire is happening to the state next to Arizona and it's blowing all the smoke into our area. I have had headaches over the past several days. Not good to be outside right now. It's way too hot here. I'll be gone for awhile and checking blogger when I get the chance. If you don't hear from me, it's because I'm with my family in the northern part of the country....cooler, rain(much like your own climate), and next to Lake Michigan....it should be gorgeous for the next week. Hope I get some great shots to share. Hang in there....I'll be sending sunny thoughts your way.

Ragged Robin said...

Hi Chris - Keep sending those sunny thoughts - they are working - I can actually see the sun today :). Hope it gets cooler and less smokey where you are soon. Have a great time with your family and enjoy the change in weather :). Look forward to catching up when you return! All the best Caroline

ShySongbird said...

I think these garden bird surveys are always useful although to be honest (and I'm sure it's me being thick!) I can't understand the point of the body weight bit!!! Any ideas gratefully received :-)

Ragged Robin said...

ShySongbird - TBH I was puzzled too about the weight bit! I've had another look at the BTO website about the Survey and it answers the question there "Why biomass and not numbers?" and I quote direct " Although we are actually collecting information on the numbers of birds seen in gardens during the survey period (something that we will use for other parts of our analysis), we need a sensible measure by which we can compare gardens with different types of birds visiting. One Woodpigeon will eat considerably more birdfood than one house sparrow so it makes sense to use a measure that can account for this. Biomass provides the measure".

Perhaps all will become clear when they eventually produce the scientific paper or in Springwatch this week! (Although I missed it tonight as everyone was watching the Jubilee Concert).

To be fair I think they are also using data from Garden Birdwatch and Garden Bird Feeding Survey which just asks you to record maximum count at any one time during the week of each species visiting the garden or in the case of the the latter taking food or water.

ShySongbird said...

Thanks for your answer Caroline. I had looked at the BTO explanation and am afraid Mrs Thick as a Brick still doesn't really get it but as you say things may become clearer eventually. We too missed Springwatch :-( We were watching the concert and hadn't realised it was on, probably because it felt like a Sunday!

Ragged Robin said...

ShySongbird - Hi again Jan - I think I'm Mrs Thick as a Brick too!! as I really can't see it either. I might be wrong but I have a recollection of reading somewhere (but I can't refind it!) that the higher the biomass the higher the productivity of the garden - which I understand even less. Perhaps it is being used as just one measurement of how productive a garden is or there again perhaps they decided it was a good gimmicky idea to get people interested!