Thursday, September 13, 2007

Hummingbirds

In August, I posted several times about the territorial hummingbirds and the fights that were taking place in my yard. After observing a rather nasty and upsetting fight, I declared that I was no longer going to feed the hummingbirds from a feeder because they seemed to fight worse over my feeder than my flowers. I was not expecting this statement to cause controversy. Obviously some people feel rather strongly about feeding hummingbirds because this topic from my blog was discussed on a hummingbird forum and some people even got a little personal and made fun of me for my decision.

Being a very curious person, I wanted to know for sure whether the hummingbirds actually do benefit from the feeders. I wondered if the feeders were more harmful than helpful. I also wanted to learn more about the nature of hummingbirds and if indeed they would fight to kill.

I made a quick trip to my wonderful local library and checked out several books on hummingbirds. It was interesting reading and I learned a lot more about the fascinating creatures I had been observing.

Here are a few interesting Hummingbird facts:

According to Sherri L. Williamson, co-founder of the Southeastern Arizona Bird Observatory, in A Field Guide to Hummingbirds of North America, hummingbirds are the least social of all birds. "In fact, much of their behavior is acutely anti-social, ranging from strained tolerance of other hummingbirds to violent confrontation." She goes on to say that, "Territorial battles between hummingbirds rarely result in death." However there is a picture in the book of two hummingbirds that fatally impaled each other.

According to the 21st Century Gardening series Brooklyn Garden Hummingbird Garden, hummingbirds are unique to the Americas and only 22 species are found in the US. The ruby-throated hummingbird is the only species found regularly east of the Great Plains. It is the only species to breed east of the Mississippi river.

Hummingbirds are generally better pollinators than bees because they feed continuously from dawn to dusk.

The hummingbirds need a high energy diet to provide fuel for flight speeds of up to 66 mph; normal flight speed is 25-30 mph.

They typically weigh about 4 grams but their body weight can double before migration. They can drink twice their weight in sugar water each day.

Hummingbirds use sticky spider webs for nesting material and they also eat the insects caught in the spider webs.

The general consensus from what I have read is that feeders are good for the hummingbirds and also for the environment. Hummingbirds are excellent pollinators and many plants, from flowers to trees, across their migratory path receive this benefit. Since most communities do not have adequate natural nectar sources the feeders supplement the high metabolism rate of the hummingbirds and have also allowed them to expand their normal range.

Since it is very important for hummingbirds to eat every couple of hours, and knowing they had been relying on my feeders as their food source, and also knowing there are very few feeders or flowers in my neighborhood to sustain them, I decided to reverse my decision and put the feeder back outside. I also followed the advise of Bisbee Border Birder Bloggers and I put another feeder in the front flowerbed. Besides, I missed watching them. It is a fun treat to sit at my window, within inches of these amazing birds, and watch their entertaining antics.

I believe the kind of fight I witnessed was a rare incidence due to the fact that it was not a fair fight, since one hummingbird was already injured or sickly. The attack was more aggressive in nature because the injured hummingbird couldn't fly away or defend itself. I do believe that in this case the fighting would have resulted in death had I not intervened.


I have watched and carefully observed, even getting up early in the morning to sit in my car just to get a good view of the front feeder, and yes, hummingbirds are very aggressive, territorial, mean and anti-social, but usually the fights are harmless tussling and chasing. Although one morning I was stunned at the loud thud from two of them hitting each other.

I'm still seeing a few visitors at my feeders. Now that the evenings are cooler, I wonder each day if it will be my last time to see them. I cleaned my feeder today and put in fresh nectar hoping that tomorrow I'll see them again. I read that they have very good memories and will return each year to their summer home. I hope they do remember and bless me with their entertaining antics again next year. I'll be planting more flowers they like just to make sure.
Here's the list of plants they like, ones I already plant (*) and others I might consider planting:
Beautybush
Bee Balm
Butterfly weed
Butterfly bush*
Cardinal flower
Catmint
Coleus*
Heuchera
Daylily
Delphinium
Four-o-clock
Foxglove*
Hibiscus*
Hollyhock
Hosta*
Impatiens*
Lantana*
Liatris*
Lobelia
Morning glory (red)
Phlox
Rose of Sharon
Sage, Salvia*
Weigelia*
Zinnia*


Edit: Entangled gave a link, in her comment to this post, to the University of Maine Cooperative Extension. As she said, "they seem to lean toward the position that feeders are bad, but they apparently tried to write it in a way that wouldn't antagonize those who put up feeders."
I personally have observed that the hummingbirds do not fight over my flowers like they do my feeders, however several people disagreed with that statement and said that hummingbirds fight the same over flowers as they do feeders. Here is a quote from the UMCE site, "Because hummingbirds are very aggressively territorial, experts suspect that competition at feeders may be extreme and very stressful. "
Well, now I'm back to square one; are feeders really beneficial or are they harmful? It would be nice if the "experts" could agree.
Edited again to include comment by Sherri Williamson co-founder of Southeastern Arizona Bird Observatory and author of Peterson Field Guides Hummingbirds of North America.
Sheri Williamson said...
A few comments on this post and its comments:* About my field guide, you wrote "However there is a picture in the book of two hummingbirds that fatally impaled each other." Though there were no human witnesses to the incident that led to these birds' death, the full photo caption states that it is believed that they impaled each other when the arcs of their dive displays intersected. This would have been an accident, not the direct result of aggression.* The Brooklyn Botanic Garden book on hummingbird gardens is misleading about the distribution of hummingbirds in the U.S. Ruby-throated is the only species that commonly nests east of the Great Plains, but several other species occur in the eastern states in fall and winter. Many of these birds, which once would have been written off as doomed, have been documented to survive the winter, migrate, and return to the same location up to 9 winters in a row! The fact that most of these wintering hummingbirds visit feeders has allowed us to document this phenomenon but probably also contributes to their survival.* Though the University of Maine Extension Service's hummingbird info page is mostly accurate, the anti-feeding sentiment is misguided and supported by misinformation. The claim that "experts suspect that competition at feeders may be extreme and very stressful" is probably based on the rantings of an anti-feeding activist who commonly uses disinformation to push his agenda. As far as I know, none of the bona fide experts in the hummingbird research community believes that the levels of aggression around feeders are either unnaturally extreme or dangerously stressful. They are far more concerned about poor feeder maintenance, red dyes and other unnatural additives, cats, windows, and pesticides. The statement that "Artificial nectar does not provide the nutrients that are in floral nectar" is also incorrect. Scientific analysis of the nectar of hummingbird-pollinated flowers has shown them to be basically a solution of sugars in water with only in minute traces of other nutrients. Nectar does not have to provide complete nutrition in liquid form because hummingbirds get protein, amino acids, vitamins, and minerals from the insects and other invertebrates they eat. * Though there are no formal studies on the rates and causes of mortality of hummingbirds that do and do not use feeders, it's feeder-using hummingbirds that have set every longevity record so far. We're talking about 8 years for most species and a maximum (so far) of 12 years, far longer than anyone would have guessed such a small bird could live. As I once wrote to a colleague dealing with a similar controversy, if using feeders is killing hummingbirds, it's doing so v-e-r-y, v-e-r-y s-l-o-w-l-y.* As Paula said, it's your garden, and you get to decide what you put in it, but I hate to see people basing their well-intentioned decisions on misinformation and sharing that misinformation with others.
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Sheri, your book says that you are, "one of North America's foremost experts on hummingbirds". I am honored that you would take the time to respond to this confusing dilemma. Thank you for making these corrections and "setting the record straight". I don't want to be responsible for sharing misinformation. I'm very glad to know your opinion on hummingbird feeders.



8 comments:

Pam/Digging said...

Thanks for the hummer factoids. I can see why you put your feeder up again---you got some great shots by knowing where they'd be dining. How smart of you to use a car blind to take their photos!

Your hummingbirds are more brightly colored than mine, which are only faintly green. No ruby throats either. Maybe someone will ID them for me one day. (Yes, I'm that lazy.)

Entangled said...

I've often wondered whether feeders help or hurt birds, and this is obviously an emotional subject for a lot of people. I wonder if there are any good scientific studies about this. My own personal conclusion is that it's probably a toss-up and I put up feeders because I like to see the birds. But if I had witnessed the behavior that you saw, I don't know how I'd feel. The University of Maine Extension Service has a detailed publication online about Ruby-Throats, and they seem to lean toward the position that feeders are bad, but they apparently tried to write it in a way that wouldn't antagonize those who put up feeders.

I love your photos!

Robin's Nesting Place said...

Entangled, thanks so much for the link. Opinions certainly do vary on the subject and it's really hard to know what is really true. The link you provided does suggest that feeders cause more extreme aggression. I thought so.

Paula said...

No matter what position you take, there will always be someone to oppose it. I wouldn't let it bother you. It's your garden and you get to decide what you put in it. I do appreciate your willingness to learn more about the hummingbird, though. Enjoy your garden any way you see fit!!

Sheri Williamson said...

A few comments on this post and its comments:

* About my field guide, you wrote "However there is a picture in the book of two hummingbirds that fatally impaled each other." Though there were no human witnesses to the incident that led to these birds' death, the full photo caption states that it is believed that they impaled each other when the arcs of their dive displays intersected. This would have been an accident, not the direct result of aggression.

* The Brooklyn Botanic Garden book on hummingbird gardens is misleading about the distribution of hummingbirds in the U.S. Ruby-throated is the only species that commonly nests east of the Great Plains, but several other species occur in the eastern states in fall and winter. Many of these birds, which once would have been written off as doomed, have been documented to survive the winter, migrate, and return to the same location up to 9 winters in a row! The fact that most of these wintering hummingbirds visit feeders has allowed us to document this phenomenon but probably also contributes to their survival.

* Though the University of Maine Extension Service's hummingbird info page is mostly accurate, the anti-feeding sentiment is misguided and supported by misinformation. The claim that "experts suspect that competition at feeders may be extreme and very stressful" is probably based on the rantings of an anti-feeding activist who commonly uses disinformation to push his agenda. As far as I know, none of the bona fide experts in the hummingbird research community believes that the levels of aggression around feeders are either unnaturally extreme or dangerously stressful. They are far more concerned about poor feeder maintenance, red dyes and other unnatural additives, cats, windows, and pesticides. The statement that "Artificial nectar does not provide the nutrients that are in floral nectar" is also incorrect. Scientific analysis of the nectar of hummingbird-pollinated flowers has shown them to be basically a solution of sugars in water with only in minute traces of other nutrients. Nectar does not have to provide complete nutrition in liquid form because hummingbirds get protein, amino acids, vitamins, and minerals from the insects and other invertebrates they eat.

* Though there are no formal studies on the rates and causes of mortality of hummingbirds that do and do not use feeders, it's feeder-using hummingbirds that have set every longevity record so far. We're talking about 8 years for most species and a maximum (so far) of 12 years, far longer than anyone would have guessed such a small bird could live. As I once wrote to a colleague dealing with a similar controversy, if using feeders is killing hummingbirds, it's doing so v-e-r-y, v-e-r-y s-l-o-w-l-y.

* As Paula said, it's your garden, and you get to decide what you put in it, but I hate to see people basing their well-intentioned decisions on misinformation and sharing that misinformation with others.

Apple said...

Thanks for the lesson! I love my hummers. I have flowers and my neighbor has feeders. They seem to visit us both regularly. We think there are two pairs but there could be more. They do chase each other. Their favorite flowers here seem to be bee balm, penstemon and salvia. I have seen them at the hostas. Now that those plants are mostly done I'm seeing them at the butterfly bushes and zinnias. I have hollyhocks but haven't seen them there - doesn't mean they haven't, just that I haven't seen them.

Pauline Barrett said...

I live in an urban area outside Seattle, WA where we have been feeding Anna's hummers, in 3 sites, for a couple of years. They over-winter, and flit in and out of the evergreen trees that surround our place. Finding a nest would be impossible but we know there are at least 2. Watching their agrression is heartbreaking, but it's reassuring to see that it's "normal."

Michelle said...

Thanks so much for your posts on hummers. They are my favorite birds. I have 3 feeders in my garden. Two of the feeders are dominated by one or two birds. One of the feeders, not always the same location, is shared by at least 9 hummers. At dawn and particularly dusk, all four ports are occupied at once with the other 5 hummers hovering around and darting in to get a share. There are even 2 hummers that will perch together at a single port and share! Anna's reside year round here and nest in the garden. In the spring there have been Allen's migrate through. This spring there were 3 or 4 of them that stuck around and dominated one of the feeders for a month.