A lesson in counting

The Canons Farm Linnet flock is not the easiest group of birds to count. They rarely combine together and prefer to feed in smaller groups spread across several adjacent fields, but every so often they do meet up and wheel across the skyline before breaking up once more. Such a ball of activity calls for snap judgement of numbers present - it is far easier to count the smaller aggregations, and as long as you keep your wits about you and do not double-count, add those figures up to get a (fairly) accurate count. Sometimes they do the right thing...

Yesterday afternoon the birds came together over Tarts Field, and whereas 150 peeled away and landed back on the stubble, the rest landed in a nearby tree. I took a picture of this gathering and then started to count the perched birds, but I was stymied by a continual procession of small flocks peeling off and disappearing into neighbouring fields. How many were there? I reckoned at least 200, maybe even 250. Don't cheat, what do you reckon?


This morning I put the image on a computer screen and methodically counted them, placing a colour square on each bird so as not to double-count. Each group of 100 were given a different colour. Some squares are on top of each other and cannot be seen as individual squares. The final number? 426.


426 must be a minimum as there will surely be hidden birds (behind other birds or branches). My overall count of 500 from yesterday now becomes a minimum of 575. They will soon break up, so I might be tempted back to have another count.

In other news: Spring migration felt as if it had really started on the farm yesterday, with a second calendar-year male Black Redstart and three Stonechats consorting together along the fence line at Reeds Rest Bottom, the former a dusky female-type plumaged bird exhibiting an obvious wing panel.

Comments

Derek Faulkner said…
Blimey Steve, you must be getting severely bored.
3 March 2020 at 14:24
Simon Douglas Thompson said…
Knocks the flocks of 30 odd birds I've seen into a cocked hat
3 March 2020 at 20:38
Dave Boyle said…
There's a count function in photoshop - you just click & it numbers what you click on & you can have different criteria of things you count, I've used it a lot for Black-billed Gulls where you're counting nests & individuals - its really handy!
4 March 2020 at 04:52
Steve Gale said…
Derek, not so much bored as plenty of spare time on my hands.
Simon - in some years 30 Linnets would be a good count here too.
Dave - I wasn’t aware of that function, thanks!
4 March 2020 at 08:53
Post a Comment

Popular posts from this blog

Goldfinches and Lavender

Image
We have three medium-sized Lavender bushes in our back garden. Throughout the summer the flowers (which last for several months) are a magnet for insects and give off a most restful aroma. As tempting as it is to cut the dead stems in the autumn, we always leave them, as we know that during the late winter we will get visitors to feed on the seed heads... This video was taken from the kitchen window this morning. We will normally see one or two birds over a few days, but have had up to 14 at once. We never tire of watching them. Lavender is a wonderful plant to have in the garden, with year round natural history benefits. So what are you waiting for? They are readily available at a garden centre close to you right now! There is an historic association with Lavender in this part of northern Surrey and south London. Lavender fields have been harvested for many years, with one particular field close to Woodmansterne being very popular with day trippers. A significant proportion o...
Read more

Welcome back!

Image
In November 2005 I purchased a pair of Swarovski 10x42 EL binoculars from The London Camera Exchange shop in Guildford, for the then princely sum of £899. These bins have served me well, with almost daily use in all types of weather, testing their durability to the maximum - salt water spray, deluges of rain, 38C temperatures, dust, dirt, slight knocks... and apart from the armour coating that had started to bubble and come away from the body, nothing to be alarmed about. Then, in the summer of 2022, I noticed that I had a problem when close focusing - the outer focusing wheel would lose grip and it would take me an age to regain a middle-ground distance of focus - plus, over the next few weeks this outer focusing wheel became loose. I resorted to the use of tape to keep it all in place, but realised that I had to do something about it in the long run. For a while I did consider buying a new pair - after all, they were then 17-years old - but they were still optically superb. It seemed...
Read more

A special day

In birding, timing can mean the difference between an average day in the field and that of a spectacular one. Good timing can be helped by reading the weather conditions correctly, or understanding local conditions but it is more often down to pure luck. In this case, I just got lucky... I had not visited Dungeness since March 2022, quite a gap for me. It was high time that I once more trod the shingle and my timing of a visit was down to several factors, mostly a personal liking for mid-late autumn but also because I needed to be at home until September 20th and could not make the journey south until then. I also chose to stay at the bird observatory for a few days rather than make it a day trip. All this conveniently found me stepping outside the observatory's back door in the breaking dawn of Sunday 22nd September, quickly making my way to the fishing boats, an area I prefer to stand to best appreciate any visible bird migration, an aspect of birding that I find exhilarating.  A...
Read more