How Many Hummingbirds Do You Have

While far from being foolproof, here is how you can estimate how many Hummingbirds you have coming to your feeder or feeders. If you want to be compulsive about it, you need to establish what kind of hummers you have at your feeders and whether they are fattening up for their migration. Since most of our readers are in North America and since it is late August, you can safely assume that your hummers are fattening themselves up now. It is a long way across the Gulf of Mexico and there is no where to land and rest. Accordingly, Hummingbirds who make the trip fatten up before departing. They will utilize all the extra calories on the trip and arrive a couple of days later dangerously underweight. They’ll do the same next spring when they return.

A Hummingbird eats almost exactly its body weight in 25% sugar solution each day. They also need protein which they get primarily from the insects they consume. So, if you are east of the Mississippi and are feeding Ruby-throated Hummingbirds here is the data. A Ruby-throat getting ready to depart for its wintering grounds will weigh about 5.5 grams. This is almost double its body weight from when it arrived in the spring, about 3 grams. Therefore, each Ruby-throat you have now is probably consuming about 5 grams of nectar from your feeder each day. All you have to do to calculate how many you have feeding is divide the total weight of the nectar you feed in grams by 5 grams and you’ll have a pretty good estimate of how many birds you are feeding.

Simple, huh?

Unless, of course, you have no idea how many grams of nectar you are making. We certainly didn’t.

We could, I suppose, make you look it up so – as they tell us as kids, “You’ll remember it longer if you look it up.” – or we could just tell you. Since we are shamelessly trying to build readership at our new blog, we don’t think it is safe to try your patience so we’ll just tell you that a 32 ounce feeder contains 946 grams of water. Rounding up to account for the weight of the dissolved sugar, let us assume a 32 ounce feeder contains 1000 grams of nectar. An eight ounce feeder would contain 250 grams of nectar. Assuming an average hummingbird weight of 5 grams in the autumn you would be feeding 25 birds if you are feeding 8 ounces a day. Or 50 birds for 16 ounces or 100 birds for 32 ounces or 200 birds for 64 ounces. More or less. Unless our math is wrong. Or unless the 1973 study of hummingbird consumption is wrong.

This seems like a high number to us and we would love to hear from anyone who has any different methods for determining how many hummingbirds are feeding.  We’d like all the help we can get.  We’ll do another post of other ideas.

This information comes from an excellent book by Dan True entitled Hummingbirds of North America. We think this is his website. We will try to confirm that and post the results. (Actually, Mr. True – who has made an appearance at this blog once before as the curator of the film of the Greater Roadrunner killing the rattlesnake – failed to tell us how many grams there are in an ounce of water or nectar. He “misoverestimated” our knowledge of the weight of water in grams. But I have loved the man since I was a little boy watching his weather forecasts so I forgive him.


6 Responses to “How Many Hummingbirds Do You Have”

  1. Running the hummer numbers « Life, Birds, and Everything Says:

    […] the hummer numbers I just ran across a post from last August on The Fat Finch Bird Brain Blog that addresses the frequently asked question about how to calculate the numbers of hummingbirds […]

  2. fatfinch Says:

    Thank you for your comment to this post and the helpful information you have provided us and our readers. We look forward to trying out the suggested counting methods.

  3. HummerLover Says:

    I think the method of hummingbird counts you give significantly over estimates bird counts. And the calc is needlessly complex. Regardless of the concentration you mix your nectar, all that matters is sugar content. I use 3.3 lbs sugar per day in my feeders during peak summer months (about 100 lbs/mo and ~700 lbs per year).

    From my online readings, I’ve seen claims that a typical hummer consumes half its body weight in sugar per day. If so, the calc shows I am feeding about 850 hummers a day. From my unscientific estimates of watching my hummers thru my home office window all day long for years, I think that calculated number is multiples of what I actually feed. I guess I am feeding 100-200, but that they are consuming far more sugar than thought. Even if I assume they are consuming their body weight (about 3.5 grams for Annas) every day, I still am “supposed” to be feeding 425 a day – I just don’t think I do based on the bird’s behavior.

    I don’t have bee/wasp problems and don’t have woodpeckers, orioles or bats visiting, so it’s 100% hummingbirds. As such, I’m confident that the birds are the only ones eating the sugar and that each bird eats a lot more sugar than conventional thinking presumes.

    • fatfinch Says:

      We have the same intuitive feeling that we are not feeding as many as the method indicates and a logical explanation of that would be that the each hummingbird eats more syrup than conventional wisdom supposes. Moreover, you long experience observing them corroborates that. We are, however, unaware of any good data on the point.

  4. david adkins Says:

    ok, i read all this and im still lost. my son just brought home a feeder and we put it out. im using a 1/4 cup sugar to 1 cup water. i have been making 2 cup mixing and it take about 3 days or less to empty. we have only i counted five different birds. can five birds drinks 2 cups that fast? if anyone can give me a simple guesstimate of about how many….and this is in late may.

  5. HummerLover Says:

    5 hummers consuming 1/2 cup (ie 125 grams white sugar) over 3 days is 41.67 grams per day/5 hummers = 8.33 grams per hummer per day (Anna Hummingbirds weigh ~3.5 grams). So if only 5 hummers, they are consuming 2.4x their weight in sugar every day. It seems a bit high for just 5 hummers, but not outlandishly so – but it is 5x more than what the “experts” say they “should” be consuming. I suspect you have a few more hummers than you realize.

    From years feeding my several hundred hummer strong flock, I think hummers can consume ~2x their weight during active summer days. They are noticeably hungrier in cooler weather (probably have more difficulty finding natural sources of nectar – or there are fewer insects to catch and so they have more time to stock up on sugar).

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