Counting 102—birds at feeders

By Team eBird 14 Feb 2016
Northern Cardinal Cardinalis cardinalis

A couple years ago we published the Counting 101 and Counting 201 articles, tutorials for how to more effectively and accurately count birds that you’re seeing. Counting 101 focuses on the basics—how to keep track of birds throughout a birding outing, and how to count a flock in parts to estimate the total. Counting 201 takes this a step further, dealing with large numbers and flocks of birds in motion. Counting 102 is intended to take these counting best practices and apply them to feeder birding—a slightly different counting problem, but an important one to address. For anyone who has wondered how best to count and eBird the birds visiting you feeder—this article is for you.

You wake up in the morning, and—first things first—time to check the feeder. Whether your feeder is nectar-filled and aswarm with frantically feeding hummingbirds, a thistle tube liberally coated with finches, or a tropical fruit feeder dripping with gaudy tanagers—there is always the same question. How many birds are there? This question becomes especially difficult when you’re watching feeders for an extended period of time, and the feeder attendees are in constant flux. While you are eating breakfast, paying close attention to the feeders, how many birds are coming and going? Without marking each bird with an individual identifier (e.g., color banding) we’ll never know for sure, but we can always make our best estimate.

How to count birds at your feeder for entry in eBird

Report the highest number of individuals seen at one time during the observation period, as well as any clearly different individuals

The highest number of individuals at one time is an easy concept, although it can be difficult in reality. If you’re unsure how to get started with counting all the birds present, Counting 101 should be able to help. However, the highest number of individuals also ties into the more difficult aspect of counting feeder birds: clearly different individuals. Obviously if you see 6 female Northern Cardinals and 3 males, and later see 6 males together, then you have at least 12 different cardinals at your feeder. Your report to eBird should reflect this.

Different individual birds can be recognized in several different ways, often due to an obvious difference in age or sex of the bird. These can be as striking as a male versus female Northern Cardinal—red vs. brown. They can also be more subtle, such as different ages of Downy Woodpeckers (red on the crown vs. back of head in fall; or potentially more detailed aging via molt limits in wing coverts) or determining American Goldfinch age or sex in fall and winter. It can also be natural variation within the species that isn’t tied to age or sex, like White-throated Sparrow head stripe color. Some White-throated Sparrow head stripes are are white-on-black with bold yellow supercilia, some are tan-on-brown with almost no yellow. These individual differences can often stand out, and help with making sure you’re counting all birds present.

Sometimes birds can lose all the feathers on their head at once—certainly a unique individual!

Sometimes birds can lose all the feathers on their head at once—certainly a unique individual!

There can also be uniquely identifiable birds due to plumage or other physical characters. Perhaps a Gray Catbird that has an overgrown bill tip, giving it a cross-billed appearance, or a House Finch that has a few leucistic (i.e., white) feathers, a splash of white on their brownish countenance. Birds that are missing or replacing feathers can often be distinctive as well, whether there are some tail feathers missing, overall patchiness of the plumage (e.g., a blotchily brown and red Northern Cardinal in the fall), or sometimes even completely bald heads!

If you really want to get the best idea of how many birds are at your feeder, this is a great way to learn more about the species that visit your yard. The more you understand about how old an individual is, or whether it is male or female, the better understanding you’ll have of your own personal feeder community. Using the Age/Sex grid in eBird can be a great way to keep track of what is visiting, and allow you to record the age and sex of your feeder visitors throughout a single day or across days.

Add age and sex information for any birds in eBird

Add age and sex information for any birds in eBird!

All of this talk about individual birds and identifying age and sex is not required for eBirding, but is certainly a fun way to learn even more while watching your feeders. Paying attention to the age and sex of birds in the field deepens your understanding of their movements, breeding success, and presents new, fun challenges beyond species identification.

What is most important is to report the highest number of individuals seen at one time during the observation period, as well as any clearly different individuals. This is an admittedly conservative counting method, since many more birds may be visiting than you can confirm by this method, but we always encourage conservative counting in eBird.

Of course, one of the most important parts of eBird and counting is to have fun while doing it! Hopefully this article will give you a good primer for how to more thoroughly understand the community of birds visiting your feeders.