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Another Eucalyptus Myth: Bird Death According to Audubon

November 20, 2010

As we have said in other posts on Million Trees, those who demand the destruction of non-native trees justify their demand by making many critical claims about them.  One of the most disturbing of these claims is that eucalypts kill birds.  Reprinted here with permission is an excerpt from an article in the April 2010 newsletter of the Hills Conservation Network which debunks this myth.

The Hills Conservation Network is a group of residents in the Oakland-Berkeley Hills who advocate for fire safety without clear-cutting non-native trees.  Most of the members of the network are survivors of the 1991 fire in their neighborhood.  Some lost their homes.  Some lost members of their family.  They are highly motivated to improve fire safety in their neighborhood and they strongly believe that fire hazard mitigation can be achieved without destroying all non-native trees. 

Please visit their website  to see other issues of their newsletter which is a valuable source of information on the subject of fire hazard mitigation.  You may subscribe to their free on-line newsletter by sending an email to inquiries@hillsconservationetwork.org.

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BIRDS AND BLUE GUM: LOVE OR DEATH?

Brochures distributed by various agencies in northern California state that the flowers of eucalyptus trees kill birds. According to these brochures, birds feeding on insects or on the nectar of eucalyptus flowers may have their faces covered with “gum” and die of suffocation. Luckily for the birds, according to one brochure, most of them prefer native vegetation, and avoid eucalyptus groves.

These stories are, of course, extremely upsetting to all of us who love birds.

The bird-suffocation story began with a 1996 article by Rich Stallcup, a legendary birder who writes for the Pt. Reyes Bird Observatory. In the PRBO Observer, he reported that, on one day in late December, he counted, in one eucalyptus tree:  20 Anna’s Hummingbirds, 20 Audubon Warblers, 3 Orange-crowned Warblers, 10 Ruby-crowned Kinglets, a few starlings, 2 kinds of orioles, a Palm Warbler, a Nashville Warbler, a warbling Vireo, and a summer Tanager.

That was an unusually large number of birds, even for Stallcup to see in one tree, but what most surprised him, he says, is what he found under that blue gum eucalyptus tree: a dead Ruby-crowned Kinglet, its face “matted flat from black, tar-like pitch.”

Years before, Stallcup recalled in the article, he had found “a dead hummingbird with black tar covering its bill” under eucalyptus trees. This was all Stallcup needed to come up with his theory about what had happened.

This theory is now stated as fact in restorationist literature and it is stated three times as fact in the “Wildfire Plan”/EIR issued by the East Bay Regional Park District in August 2009.

Stallcup theorizes that North American birds are different from birds indigenous to Australia. He speculates that North American birds such as kinglets, warblers, and hummingbirds have evolved short, straight bills while Australian birds evolved long, curved bills. Thus, he says, when American birds with short bills seek nectar or insects on eucalyptus flowers, they have to insert their whole head into the blossom, so they get gummy black tar all over their faces.

Misleading illustration from Stallcup article

We have great respect for Stallcup’s ability to identify birds.  But we have a few problems with his theory.

 

Australian Weebill. Credit: Stuart Harris

1. A bird-loving friend who has photographed birds in Australia points out that Australian field guides show birds with a wide variety of bill length and curvature.  When he was in Australia, he saw birds with small bills just like American kinglets and warblers.  “How do you suppose the Australian Weebill got its name?” our friend asked.  Many of us not so familiar with Australian birds have seen parakeets and other small small-billed parrots native to Australia. Weebills  and many other American and Australian birds with small bills forage on eucalyptus leaves or flowers.

To see more birds of Australia, go to this terrific website. It features photos of many small-billed birds. 

 
 
 
 
 

 

Blue gum eucalyptus flowers on tree, March, 2010. Credit: John Hovland

 

 

2. Where’s the gum? The flower of a blue gum eucalyptus tree has no gum, glue, or tarlike substance on it or in it. The gum in “gum trees” refers to the sap or resin that, in some species, comes from the trunk. Other species of gum trees, such as the sweet gum (Liquidambar) are common sidewalk trees in Berkeley and Oakland. The flowers on the blue gum eucalyptus are white or cream-colored with light yellow or light green centers. There is no black, sticky, gummy or tarry substance in or on the living flower. In fact, both the Ruby-crowned Kinglet and the Australian Weebill are leaf-gleaners. They take insects off leaf surfaces, not from flowers. If the kinglet had gum on its face, the gum did not come from a eucalyptus blossom.

3. A euc flower looks most like a chrysanthemum, with longer petals. Unlike a morning glory, the euc flower is not shaped like a tube that a bird would need to poke its bill into to get nectar or insects. A hummingbird is more likely to pick up a sticky substance from inside a cup-shaped tulip, poppy, or any of the tiny tube-flowers such as California fuchsia, Indian paintbrush, watsonia, or honeysuckle that hummingbirds love. Common sense tells us that no bird, even a tiny one, could suffocate while feeding on a euc flower or leaf.

 

Watsonia, Willow Walk, Berkeley, 2010. Credit: John Hovland

4. We have all seen hummingbirds poking their beaks into tube-like flowers. If you peel back these tube-like flowers, you will sometimes find a sticky substance on your finger.  You’ve probably seen birds, especially tiny hummingbirds, sipping from these flowers. How do they escape getting nectar on their faces? An article in the NY Times proves truth is stranger than the fiction of suffocated hummingbirds. The article explains that a hummingbird gets nectar from a flower by wrapping its tongue into a cylinder to create a straw about ¾ inch long extending from its bill. This means that a hummingbird’s face does not touch the surface of a flat type of flower such as the flower of a blue gum eucalyptus.

After Stallcup wrote his article in 1996, it was accepted by birders and eucaphobes all across America. In January, 2002, Ted Williams, wrote about the “dark side” of eucalyptus in his opinion column called “Incite” for Audubon Magazine

Stallcup, he wrote, had told him he had found 300 dead birds over the years “with eucalyptus glue all over their faces.” Williams wrote that the bird artist, Keith Hansen, who illustrates Stallcup’s articles, had found “about 200 victims.”(How did one kinglet and one hummingbird in 1996 add up to 500 victims by 2002 even though few if any other people have seen even a single victim?)  Williams and Hansen also describe the suffocating material as “gum.”

Williams, in that same over-the-top column, dares to contradict Stallcup, claiming that he has heard only one Ruby-crowned Kinglet in a eucalyptus grove, and has never actually seen any birds in eucalyptus trees. Yet he repeats (and exaggerates) Stallcup’s story about eucalyptus suffocating birds. The National Park Service, U.C.,  EBRPD, and the Audubon Society   have spread Williams’ interpretation of Stallcup’s story—apparently without questioning any part of it.

Stallcup and Williams are bird-lovers and writers. They are not scientists. David Suddjian, a wildlife biologist, has read Stallcup’s theory about birds suffocating on the “black pitch” of eucalyptus flowers, but in his article, “Birds and Eucalyptus on the Central California Coast: A Love-Hate Relationship,” he casts doubt on Stallcup’s claim that the kinglet (and other birds) could have been suffocated by eucalyptus flowers. Here is an excerpt from his article:

“. . . in my experience and the experience of a number of other long-term field ornithologists, we have seen very little evidence of such mortality.  It has been argued that the bird carcasses do not last long on the ground before they are scavenged. However, when observers spend hundreds of hours under these trees over many years but find hardly any evidence of such  mortality, then it seems fair to question whether the incidence of mortality is as high as has been suggested. Not all bird carcasses are scavenged rapidly, and large amounts of time under the trees should produce observations of dead birds, if such mortality were a frequent event. . .more evidence is needed.”

The Suddjian article is not generally favorable to eucalyptus trees. However, Suddjian notes that more than 90 species of birds in the Monterey Bay Region use eucalyptus on a regular basis. Additionally some rare migratory birds bring the total to 120 birds seen in euc groves. These include birds that use eucalyptus trees, leaves, seeds, or flowers for breeding, nesting, foraging, and roosting. A complete list of birds that depend on eucalyptus trees is too long to include here. We encourage you to click on the link to the Suddjian article so you can look for the names of the various bird species and note how they use—and depend on—eucalyptus trees.

Lynn Hovland

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Million Trees Webmaster:  Shortly after this urban legend surfaced over 10 years ago, I had an opportunity to ask a local scientist about it. While attending an open house at the California Academy of Sciences in San Francisco, I was able to talk to the head of its ornithology division at the time.

He started by saying that although he had never seen a dead bird in a eucalyptus forest, there weren’t as many birds there because the eucalypts don’t offer as much food for birds as other vegetation types. (Those who bird in the eucalyptus forest without a nativist bias don’t agree with this generalization about a lack of birds, however.) He also said he hadn’t heard the claim.

Then, the scientist said that the story didn’t seem consistent with bird anatomy. He said that birds are capable of lifting their feet to their heads and clearing whatever might be accumulating there with their toes.   

Ten years and many walks in the eucalyptus forest later, we have yet to see a dead bird, but the myth lives on.

11 Comments leave one →
  1. Former Audubon member permalink
    November 20, 2010 4:14 pm

    The “Eucs Kill Birds” story is false. The story is widely told, repeated and printed by many, but it is still false.

    The reasons we know the story is false are well covered in the Hovland article and the MillionTrees commentary:
    1. Most importantly, there is absolutely no evidence to back it up. The story is 15 years old, but ornithologists do not report having seen birds killed by eucalyptus trees.
    2. The story would be easy to investigate and verify, if true. The Bay Area is heavily birded, year round, and many ornithologists live here. But still, no evidence is offered.
    3. There is no gum in eucalyptus flowers. The gum in “gum” trees is sap beneath the bark.
    4. Ruby-crowned Kinglets aren’t flower feeders.
    5. Birds routinely clean their bills, both by rubbing them on branches and by wiping them with their feet.
    6. Occasional dead birds are found in all habitats; they don’t live long. Almost half of all adult songbirds will die before this time next year. Within the last two years I have found dead birds on the beach, in chaparral, in an urban park, and in Douglas Fir forest. I don’t know what killed them, but I doubt that these habitats are special bird killers.

    The “Eucs Kill Birds” story is spread by people who know it is false, e.g. Audubon, the National Park Service, and the East Bay Regional Park District. Their antipathy for eucalyptus leads them to spread pseudo-scientific nonsense to a public that expects them to be scientifically knowledgeable.

    The moral of the story: You can say anything derogatory about eucalyptus trees you can make up, and the euc-haters will uncritically pick up and spread the canard without asking for any evidence at all.

  2. November 21, 2010 2:35 am

    This is an excellent and well-researched article. (We also published it with permission on the Sutroforest website at http://www.sutroforest.com)

    It deserves wide dissemination. The Audubon article is still being cited, years later, as a reason to hate eucalyptus trees. Only recently, someone we know was evicted from a neighborhood group for defending eucalyptus trees as a wildlife resource — and the Incite article used as justification.

  3. November 28, 2010 11:48 pm

    the internet’s place with all things bird watching : birdwatchingreview.blogspot.com

  4. January 21, 2014 1:24 pm

    An impressive share! I have just forwarded this onto a friend who was doing a little research
    on this. And he in fact rdered me breakfast simply because I
    stumbled upon it for him…lol. So alkow me to reword this….
    Thank YOU for the meal!! But yeah, thsnks forr spending time to talk about
    this sbject here on your blog.

Trackbacks

  1. Pt Reyes Light sheds light on eucalyptus myths and an arborist adds context « A Million Trees
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  3. The Ruth Bancroft Garden where plants from all over the world are welcome « Death of a Million Trees
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  5. Eucalyptus trees do NOT kill birds! | San Francisco Forest Alliance
  6. Eucalyptus trees do NOT kill birds! | Death of a Million Trees
  7. Birds and butterflies in the eucalyptus forest | Death of a Million Trees

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