Birds eating Monarchs and arctiids

[John Shuey]

To follow up on John's query about arctiids here's an interesting observation.

At Uxmal, Yucatan Mexico, I have repeatedly run a black light on a second story hotel balcony.  In the morning I always chase the moths off one by one so the hotel staff doesn't get pissed.  Kiskadees (a large tropical flycatcher) are common and perch in shrubs just off the balcony and pick off moths in the air as I chase them away.  So here's the interesting part.

The kiskadees nail almost every noctuid that gets flushed.  But for arctiids, they don't even leave their perch - they just totally ignore the moth as it flies away.  Granted this is casual observation, but I've seen it hundreds of times over visits spanning seceral years.  The fact that the birds totally ignore the arctiids suggests several things:

First - kiskadees don't like to eat arctiids
Second, kiskadees recognize arctiids from the moment that the moths start flying - some of the arctiids are not all that brightly colored - raising the question :

  Do kiskadees have really great eye sight and taxonomic skills, and can almost instantly recognize members of this family, or do the arctiids emit sounds as they fly, which announces their unpalitability?

I've always wanted to follow up with something a little more quantitative and experimental, but have never quite gotten around to it.

John Shuey





jhimmel at CONNIX.COM wrote:

> Hi Gary - I had always wondered about the palatibilty of the arctiids, or lack of, as their bright colors may suggest.  What a great opportunity you had to test it!  I remember looking up the food sources for the larvae of a number of the more colorful tigers.  I came to the conclusion that what they ate probably added more tasty zest to the bird's meal, than unpalatibility.
>
> On the other hand, the adult Euchaetes egle (Milkweed Tussock Moth), gives out about as much warning, color-wise, as a burnt out traffic light.  While the milkweed feeding larvae have the bright, contrasting colors you'd expect, the adults are crypically pale gray.  Works for them, though, since the'yre pretty common.
> I suppose being nocturnal has its advantages.
>
> Incidentally, phoebes are the biggest moth thieves in my Connecticut yard (they've been calling here now for the past week or two).
>
> JH
> :::::::::::::::::::::::::::::::::
> John Himmelman
> Killingworth, CT USA
> jhimmel at connix.com
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> -----Original Message-----
> From: Gary Anweiler <gganweiler at sprint.ca>
> To: leps-l at lists.yale.edu <leps-l at lists.yale.edu>
> Date: Tuesday, March 21, 2000 1:23 AM
> Subject: Re: Birds eating Monarchs
>
> >Howdy
> >
> >Brings to mind an experience I had a couple of years back. I had a screen
> >funnel trap for moths set up - and noted a Phoebe showing a great interest
> >in the fluttering contents.  He snapped up several as I released them.  By
> >the third day he would take them from my fingers.  As I was getting a fair
> >variety of our local Arctiid moths, supposedly brightly colored to warn
> >birds of their nasty taste, I took the opportunity to try them out on the
> >Phoebe.  He ate eveything with equal apparent relish - Spilosoma, Grammia,
> >Hypoprepia...
> >
> >I wonder if there are perhaps predators with better taste buds than birds
> >out there ???
> >I certainly was not impressed with the effectiveness of the warning colors
> >as defences againt avian predation !!
> >
> >Gary Anweiler, Edmonton AB Canada
> >
> >
>
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