Date: Fri, 9 Nov 2001 15:08:27 -0600
From: Rob Parsons <rparsons@ICENTER.NET>
Reply-To: BB for Hummingbirds and Gardening for them in the Southeast
<HUMNET-L@listserv.lsu.edu>
To: HUMNET-L@listserv.lsu.edu
Subject: Re: [HUMNET-L] word gets around

Hi y'all,

This topic intrigues me greatly. Does the presence of one (or more)
hummer(s) attract more hummers? Or does the presence of many hummers simply
indicate good hummer habitat? (Lots of nectar and insect plants with some
feeders and some good evergreen cover is what I mean by "good habitat.")

I know Nancy N. inclines to the latter. Ron R. to the former. There is
no doubt good habitat should attract the birds. I think that's a given.
If you have a great yard and are "the only game in town" you should get a
multiple hummer yard even if the presence of existing hummers tend to REPEL
new birds. If, however, there are many suitable yards and you're STILL
getting multiple birds, while other suitable yards go begging, there may
well be something in the attractor theory.

It would be quite difficult to test the hypothesis. Has anyone ever
tried broadcasting the calls of hummers on a sound system to see if there is
any change in hummer numbers? Don't laugh, this method has been used to
attract terns to suitable nesting sites! I realize terns are social beasts
whereas hummers are just beasts. Solitary, scrappy, irrascible beasts.
Hey, I see why Lanny likes them so much! ;-D

One possible weakness of the sounds of hummers attracting other hummers
is beyond the species level. Should the sound of a couple of scrapping
Rufous attract a Buff-bellied? How about a Black-chin? In the latter case,
I might expect, if there WERE a reaction, it might be to repel. Having said
that, however, there is no doubt flocks of chickadees attract unrelated
species which flock with them, so it's not a huge stretch to think of
inter-specific attraction amongst hummers.

I guess statistical analysis, to see how likely the clumping of such
essentially solitary critters is, might give some insight here, but who
knows?

Firmly seated on the fence, enjoying the speculation!

Cheers,

Rob Parsons
Winnipeg, MB
CANADA
rparsons@icenter.net

=========================================================

Date: Fri, 9 Nov 2001 16:24:37 EST
From: Ron Rovansek <Rrovansek@AOL.COM>
Reply-To: BB for Hummingbirds and Gardening for them in the Southeast
<HUMNET-L@listserv.lsu.edu>
To: HUMNET-L@listserv.lsu.edu
Subject: Re: [HUMNET-L] word gets around

Rob and HUMNETters,

In reference to the hypothesis that hummingbirds in a yard tend to attract
other hummingbirds, you wrote:

It would be quite difficult to test the hypothesis.

Perhaps, starting from scratch, it would be difficult, but we don't have to
start from scratch. The Baton Rouge Christmas Count includes a couple of
teams of hummingbird counters each year. These teams visit only known
hummingbird locations and count mainly hummingbirds. They usually have time to visit the yards that are currently reporting hummers as well as a few
yards that have proven to be good in past years. Thus the count produces a
record of known hummingbird yards (which we can presume are all suitable
wintering habitat for hummers) and the records include numbers of birds seen at each location. I am fairly sure that a decent statistician could suggest a mathematical test to determine in the number of one-hummer yards is
consistent with the hypothesis that hummers are randomly distributed through suitable habitat, versus the opposing hypothesis that hummers tend to be clumped. Biologists test such hypotheses all the time, and the technique
would not have to be invented just for humnet purposes.

Of course I have conceived this idea before now, but never have gotten around to actually collecting the data and doing the math. Maybe someday I will, but anyone else is welcome to steal my idea and test it yourself. There must be a statistician or two on HUMNET, refuge of the over-educated.

Ron Rovansek