Thank you, Nick.  It is good to have more information on the insect data. We 
have several large white oaks here and around the neighborhood and that is 
where the warblers seem to feed first, high in the canopy. On the rainy 
weather note, there is an article in today's St. Louis Post-Dispatch 
confirming that this is the "wettest start to any year on record in St. 
Louis."  We've had over 22.3 inches since the first of January. However, the 
last few years we have only gotten 80% of our normal rainfall.

I'm sure the folks to the south have had even more than that! Well, I am 
still waiting for a mini-fallout here. Mike Doyen mentioned that Indigo 
Buntings were pretty quiet. I actually had several here that were very vocal 
yesterday.  I waited 2 hours for one to come to the bubbler and had just 
given up and walked over to some plants I need to get in.  Dang, if I didn't 
look up and there he was at the bubbler, and I was away from the camera. 
One also went to the new pond a bit later, for sp. #37 there.

I guess every spring is different and that is what keeps me interested!

Margy Terpstra
Kirkwood, St. Louis Co. MO
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----- Original Message ----- 
From: "Barber, Nicholas Anthony (UMSL-Student)" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Wednesday, May 14, 2008 8:45 AM
Subject: Re: silent Empids?? and warblers- hypothesis

>A few thoughts on bird food this spring:
> Margy mentioned last year's freeze, which occurred around April 11.  The 
> freeze did particularly severe damage because we had above-average 
> temperatures in the preceding weeks in March, which sort of set spring in 
> motion fairly early.  The result was that the April freeze did more damage 
> than it would have in years with more "normal" phenology.  Spring insect 
> herbivores (especially caterpillars, which are thought to make up the bulk 
> of many songbirds' diets) appeared early too, and many were killed off by 
> the frost.  Those that weren't killed off then had to face a shortage of 
> food as so many leaves were destroyed.  At Tyson, where I do my work, we 
> were experiencing our 3rd consecutive year of fall cankerworm (a 
> geometrid, or "looper" caterpillar) outbreak, and an enormous number had 
> just emerged when the freeze hit.  A lot of other caterpillars were in low 
> abundance too.
> I just finished an insect herbivore census yesterday on white oak, and 
> colleagues in my lab finished an extensive survey in the Ozarks.  I had 
> worried that insects would be largely absent because of last year's frost, 
> but it wasn't all that bad.  A lot of caterpillars, especially 
> "leaf-rollers," which are usually very abundant, were harder to find than 
> usual.  But sawfly larvae (from the families Pergidae and Tenthredinidae) 
> were very common.  Sawfly larave look and act like caterpillars, and are 
> probably just as suitable as food for birds as caterpillars.  The crew 
> working in the Ozarks experienced similar high numbers of sawflies, but 
> more leaf-rollers as well.  As for the cankerworms at Tyson (which were at 
> outbreak numbers 2005-2007), I found exactly two this entire spring!  This 
> may not be entirely due to the freeze; typically after 2 or 3 high years, 
> this species is brought under control by an egg parasitoid.
> So as for the birds, they haven't seemed to be struggling to find food, at 
> least at my research site.  After the frost last year, their foraging was 
> focused along sunny edges that were not as frost-affected, but this year 
> the flocks are moving through continuous forest.  On some days I've 
> noticed a dearth of bird songs, but it may be weather-related, as many 
> birds seem to decrease song frequency on colder, cloudier, and rainy days. 
> And we've had plenty of colder, cloudier, rainy days over the last couple 
> weeks!
> Sorry to be long-winded about this...a disclaimer too:  my work is focused 
> on oaks and especially white oak, so patterns may be different on other 
> species I haven't been paying as much attention to.  Also, insect 
> populations exhibit a lot of spatial heterogeneity, so what's going on at 
> Tyson may be different from other sites (e.g., the cankerworms that were 
> so abundant at Tyson have never been recorded in 15+ years of censuses in 
> the Ozarks).
> Nick Barber
> University of Missouri-St. Louis
> St. Louis, MO
> [log in to unmask]
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