I finally got out shooting today after a bit of a dry spell. I was pleasantly treated to a rather large number of ducks congregating, migrating, partying.. whatever causes so many of them to get together like this. I have often wondered from some birding reports when they report thousands of a species present – how exactly do they count them? Is a certain group guessed to be 100, 1000? How many do you think bump into each other once in awhile? I think large flocks of birds are one of the most intriguing things to watch – just to comtemplate the numbers, the synchonicity they move in, and how they tend to act as a single ‘body’ at times.
From this experience this morning, there were easily millions.
HÃ ¥kan, thanks for the info!!
Hello,
Yes, bird do occasionally bump into each other. Severe accidents, observable by human eye, seem however to be rather scarce (yes, isn’t it amazing).
When it comes to counting birds, the purpose and situation determines the technique. Sometimes, during high migratory activity, numbers have to be estimated etither by projecting flock sizes (you know what 100 individuals of the species “look like”) or by counting intensily for some minutes each hour and then extrapolating the total sum.
Lake Hornborga in central Sweden is known for its mass gathering of European cranes (Grus grus). Working there, you often got the question how you accurately count 10345 cranes. At Hornborga, this is done by counting the small flocks that continuosly move from the feeding location (where they are being observed by huge numbers of visitors) to where they spend the night.
At the same lake “duck-counts” are conducted each spring and fall during stop-over. Tens of thousands of ducks are then counted and this is done by dividing the lake into different areas, which allows accurate counts.
Of course, there is a lot of other techniques being used.
Two, hopefully interresting, links follow (both in english):
At http://www.hornborga.com/eng/index.asp you can find more information about Lake Hornborga
and at http://orn-lab.ekol.lu.se/birdmigration/ is the homepage of the Migration Ecology Group at Lund University.
Best,
HÃ ¥kan
I like the questions you posed…I’ve wondered all of those myself…especially the bumping into each other one.
A sight like this still makes me stop to look.