Census Tips

A bird census is a great way to find out which birds are using a habitat at different times of the year.  As many organizations are working hard to improve habitat for wildlife, a regular bird census can document the success of those improvements by tracking the types and numbers of those birds over successive years as the habitat improves.  You will never be able to get an exact number but the idea is to develop an informed estimate.

It helps to be armed with some basic knowledge of the species that one is counting.  Raptors (vultures are included in that category) are wide-ranging hunters and tend to have big home territories.   Eagles, hawks and falcons will patrol and defend their territories from others of their species when they are nesting, and the territory may be a mile or even more in diameter.  For this reason, the protocol for raptors is to count only those numbers of birds that are seen in one view.  So if you see one vulture, for example, and then see another single vulture later on, your count is still only one vulture – because it could be the same one (unless there is some distinguishing characteristic, like missing feathers, that allow you to tell one individual from another).  If you later see two vultures together, then your total count is two (not three).  And if later you see six together, the total is six, and so forth.  Since male and female vultures look the same, gender is not helpful in distinguishing individuals.   You may be able to tell certain birds like falcons apart by gender based on their differing facial patterns, or distinguish juveniles from adult hawks and eagles, etc., especially in late summer and fall.  In that latter case, you should keep track of the # of adults and juveniles you see, and you can tally those separately to get a more accurate count.    

Many birds exhibit gender dimorphism – the males and females look different, such as the Northern Cardinal.  Things get trickier in fledging season, as in many species the young look like their mothers, with the males developing their distinctive colored plumage later in the life cycle.  When possible, counting males and females/juveniles separately is helpful for the data base.

Other small birds like sparrows have much smaller territories.  During the nesting season in prime habitat, it is not unusual to have Song Sparrows on territories that are only about 15 – 20 feet apart, near their nests.  But in the fall, these birds tend to form larger and wider-ranging foraging flocks, so you’ll have to allow more distance between the areas where you see the birds before you start adding more individuals to the tally.  Since many sparrows have a habit of staying in front of observers, i.e., they will keep flying ahead of you and sometimes join up with other small flocks along the way - if you’re not aware of this habit you could easily keep on the counting the same ones over and over as you walk the trail!   

If you are counting heard-only singing birds, keep a mental track of the direction you heard the song coming from.  You might get to see or hear the same bird that was singing later on as you get closer to it – but it still counts as only one bird! 

What do you do if you see a HUGE flock of birds – Canada Geese on a pond or flying in the sky, for example, or a winter Grackle flock, which are too numerous to count in the usual way?  The trick is to mentally divide the area of sky or water into blocks of a size where you can quickly count the individuals in each block, and multiply that number by the number of blocks in your imaginary grid.  This will of course not be the exact number, but will give you a pretty good estimate that will be in the right ball park.  To develop this skill, try it with small flocks where you have a better idea of the actual total number.

Find many more helpful tips on how to count birds here, and remember that “practice makes perfect”! https://support.ebird.org/en/support/solutions/articles/48000838845-how-to-count-birds#anchorBestPractices