Recently, a friend of mine forwarded me a post about hummingbirds:
Laura Ericson’s Blog posting regarding Hummingbirds and predators:http://lauraerickson.blogspot.com/2014/09/predation-and-hummingbirds.html
In her post, she presented an interesting postulate : That a 1985, scientific paper, written by Miller and Gass and titled “Survivorship in Hummingbirds: Is Predation Important?” is basically wrong. Now, whenever a layperson begins bashing a scientific paper, my ears perk up. I’ve spent a lot of time writing technical papers, books, and chapters for books, and I’m always interested to see how people perceive technical and scientific things. Ultimately, Laura’s interpretation of the paper lacks foundation and is meritless, and is just another piece of Internet drivel (not unlike this one). In the hopes that this blog post will crop up near Laura’s should anyone be unfortunate enough to locate and read either post, I have put the following editorial together.
I have no delusions that I can just say “she’s wrong” and then get on with life. Rather, I am presenting evidence that she is wrong and I am also asking the reader to do some independent research and see where it leads.
Originally, I thought I would post this to her blog, but I do enjoy retaining copyright, as well as the ability to consolidate all of my Internet ranting to one place. There is nothing worse that being unable to go back and remove an undesirable post (20/20 hindsight) or being unable to revise a malformed sentence.
This is the message to Laura as I originally intended to post it:
I have just a couple of question/comments after reading your blog post and the original paper you are discussing.
Question 1. The paper you mock refers to”‘natural predators’ in the usual sense” and you even quote this. Immediately, this excludes opportunistic predation and predation caused by things like cars, buildings, and cats, but your blog goes on to use these as refutation of the paper’s central argument.
That you mention cats as a hummingbird predator pretty much destroys your entire argument. “Natural” predation also excludes opportunistic predation induced by human activity, such as introduced invasive predators, or luring hummingbirds in large numbers to poorly concealed, non-exhaustive hummingbird feeders where those invasive predators lie in wait. Where backyard feeders are concerned, we may as well be in league with the hawks and the cats. This wasn’t really a question, was it?
Question 2. How many squirrels are killed by Red-tailed hawks? Squirrels are definitelyHawk food. A staple of their diet, as it were.
Question 3. How many hummingbirds per day are killed by, say, Cooper’s Hawks, which have been seen chasing hummingbirds (and vice versa)? I have never seen a hummingbird being chased by a hawk in nature myself, but even if did, a single incidence does not a pattern make. Even if 100 humming birds were killed by hawks, in the grand scheme of the food web, it is trivial. Thousands of squirrels are killed by hawks every day. Less than a thousand humming birds have been killed by hawks, possibly in the history of the species.
Question 3. It’s agreed by most people that, aside from other humans, we have no natural predators. Yet, thousands of humans are killed every year by lions, tigers, snake bites, sharks, etc. (I offer this as perspective). Are we to say, then, that humans are not apical?
Question 4. Finally, you argue the Hummingbirds’ alertness adaptation as foundation for their prey status. And it is an adaptation – it looks around a lot because it is hard-wired into its head to do that. It doesn’t mean the bird is flying around, terrified for its life all the time. So, why does it do this if it has no natural predators? Examine the adaptations of the kiwi bird for a clue. Why does the Kiwi possess such fabulous anti-arial attack adaptations when, in reality, no arial threat exists? (Hint : the Haast’s Eagle is extinct now).
In conclusion then, “chuckling” at the scientific and researched conclusions of actual scientist might best be left to disciplined minds…don’t get me wrong, I admire your work and understand and sympathize with your position that the hummingbird is a victim of opportunistic predation – I’m sure it is. I just think you went about expressing your point in a very unscientific manner, and that you victimized a very well written paper for seemingly opportunistic motives.