Taking an Attendance of Birds

We generally spend more time in places where we have something to do rather than places where we are doing nothing. For example, we spend a lot of time at home, since that is the place where we stay. We tend to spend a lot of time at our workplaces since that is where we earn our bread. Similarly, students spend a lot of time at school or college since they go there to learn something which gives them a return in the long run.

If we look at things on a longer time scale, we are to be found at home for the greatest part of the year, which is nearly 100% of the days. We could be found at our work places for almost all the working days of the year (over 70% of the days), while we are likely to be found at school for nearly 60% of the days in a year. We could thus compute an “attendance” score for our favorite canteen or cafe, or our visits to movies, and the like. And the list could go on…

Resident birds too would spend more days of the year at places where they have something to do rather than at places where they have nothing to gain from. If they are sleeping (roosting) on your tree, it is likely they are coming there every night for the whole year. If they are coming to feed in your backyard, they might be coming there for most days of the year, with a few days missed to explore elsewhere.  If it is a bird which has lost its way and is trying to get back to its normal home habitat, it might be found on your tree or in your area for a couple of days at the most. It could then be expected to move on.

Simply put, this is like the attendance a teacher would take for the students in a class. Just like there are students who maintain a high attendance score and those who do not, there would be birds which frequent an area regularly and also those which are rather irregular to that place.  So, it would be interesting to know which bird spends the most number of days at your garden or backyard, or even around your home. In comparison how do other kinds of birds fare?  Are they found all round the year there? What about the school compound? What about the plot of land which you view from your favourite office window?

So how could one maintain an attendance of the birds? Just keep a look out and mark all the days on which you see a particular kind (species) of bird in the same specified area. This could also be based on what the statisticians would call a sample. To know what percentage of days a bird spends at your garden, it is not necessary to look for them every day. Supposing we are able to do it twice or thrice a every week, we would have some hundred or a hundred and fifty days or samples to check the proportion of days they are found at your place.

If we had such data for a long enough period, for a large enough number of places, we could even say what is happening to birds in our city. We could try to know if they are going up in numbers or are coming down, or if their population is relatively steady. In nature, due to a property associated with numbers of animals, more the frequency, more would be the actual numbers of animals counted. This is because animals would try to avoid packing themselves too much together! This is also because of what a statistician would call a skew in the distribution of numbers. Since we know both abundance and frequency are related, we are doing only one thing now: We are just keeping an attendance of birds!

Maintaining the data and keeping it organized is very important and for this, one could buy an attendance register book from any stationary shop.  Enter the names of the birds where you would generally write the names of the students and you are done. Fill in the dates, the month and you are ready to record the data. Please do not be biased for or against any kind of bird. Faithfully record all that you see: even if it means that you are seeing some of them every time you are making an observation! Not having any “favorites” or “dislikes” is very important for the analysis. But just remember to avoid gaps of more than a fortnight  as far as possible.

 

KRISHNA.MB, Monday, December 21, 2009