Hi Richard,

There is indeed experimental work being done on hummingbird memory and learning. A quick literature search turned up this abstract. I thought you might be interested.

Title: A field study of spatial memory in green-backed firecrown hummingbirds (Sephanoides sephaniodes)
Author(s): Gonzalez-Gomez PL (Gonzalez-Gomez, Paulina L.), Vasquez RA (Vasquez, Rodrigo A.)
Source: ETHOLOGY 112 (8): 790-795 AUG 2006

Abstract: The foraging ecology of hummingbirds involves the exploitation of a high number of patchily distributed flowers. This scenario seems to have influenced capabilities related to learning and memory, which help to avoid recently visited flowers and to allocate exploitation to the most rewarding flowers, once learning has occurred. We carried out two field experiments with the green-backed firecrown hummingbird (Sephanoides sephaniodes, Trochilidae) in order to examine the ability of birds, first, to recall a nectar location, and secondly, to remember the location of the most rewarding flower among lower quality flowers. The first experiment showed that subjects were able to recall the location of nectar among flowers of identical appearance. In the second experiment, hummingbirds were also able to recall the location of the most rewarding nectar among less rewarding flowers with the
same appearance. The results of this study suggest that S. sephaniodes can remember the location of the most rewarding patch, facilitating efficient exploitation of flowers in the absence of visual cues related to nectar quality.

Best,

-karen.reagan

--------(snip)--------

From: Richard Carlson <rccarl at pacbell.net>
Subject: Re: [Tweeters] Hummer activity on Oak Bay. 2005 to 2007
To: Dave Nuttall <dave_nuttall at yahoo.com>, Tweeters
<tweeters at u.washington.edu>


Tweeters:

I don't know if there is experimental data, but my
hummers at Tahoe and Tucson appear to have a learning
curve and a memory. That means that once they know
the feeders are there, I'm one of the first places
that get checked when they return the next year. I'm
also one of the last spots to see the last migrants.
The result looks like they come earlier and earlier,
but I think that they're just smarter than we think.

RCC