[Tweeters] Purple Martins gleaning insects from tree branches (really).

mcallisters4 at comcast.net mcallisters4 at comcast.net
Sun Jul 14 16:10:47 PDT 2019

It would be valuable to get photos of the yellow caterpillars on these trees. I’m really curious about the species, whether it’s a native butterfly/moth or some non-native species. I tend not to range that far, being old and all.

Kelly McAllister


From: Tweeters <tweeters-bounces at mailman11.u.washington.edu> On Behalf Of stan Kostka lynn Schmidt
Sent: Sunday, July 14, 2019 10:33 AM
To: Hank H <h.heiberg at yahoo.com>
Cc: Tweeters <tweeters at u.washington.edu>
Subject: Re: [Tweeters] Purple Martins gleaning insects from tree branches (really).

Hi Hank, thanks for the observation and photos, but this is something different.

Martins routinely gather fragments of green leaves from the top of a nearby tree and use these leaves to line their nests prior to and during egg laying. This is widely described in the literature. The function of this behavior is unclear. This is the first thing that came to mind when I read about the Illwaco martins. However, in that particular case the birds were in fact gathering insects from the tree. It’s reasonable to assume the birds first noticed the insects during leaf gathering, but then went on to actually glean insects from the branches, a very rarely observed behavior.

Stan Kostka

lynnandstan at earthlink.net <http://earthlink.net>

Arlington WA

On Jul 12, 2019, at 6:36 PM, Hank H <h.heiberg at yahoo.com <mailto:h.heiberg at yahoo.com> > wrote:

I don't know if what we saw yesterday at Semiahmoo Spit is relevant to the post below. We were surprised to see a Purple Martin in a tree where it appeared to be eating a leaf. I don't know if there were bugs on the leaf. There are Purple Martin houses attached to the piers at the end of the spit. The tree was near the resort buildings, but within sight of the piers. Here is a photo.


Hank Heiberg

Issaquah, WA

From: stan Kostka lynn Schmidt <lynnandstan at earthlink.net <mailto:lynnandstan at earthlink.net> >
Date: July 12, 2019 at 7:47:06 AM PDT
To: tweeters at u.washington.edu <mailto:tweeters at u.washington.edu>
Subject: [Tweeters] Purple Martins gleaning insects from tree branches (really).

Good Morning Tweets,

Recently someone posted to OBOL an observation of Purple Martins gleaning insects from the branches of trees. I was most skeptical. However, Charles Brown’s 1997 species account, Page 7, Food Habits, capture and consumption, says, “Very rarely may glean insects off foliage or alight on ground to take caterpillars …” and cites Gullion, G.W. 1980. Purple Martins feeding on tent caterpillars. Loon 52: 190-191.

Gullion 1980 describes martins in Northeastern Minnesota eating tent caterpillars.

The OBOL observation is from the Illwaco marina on July 5. I followed up with the observer and a return to the site found the same behavior on July 8. Martins are gleaning small yellow caterpillars or something similar from birch trees at the marina. The birches are along the harbor walk, between the shops and restaurants, and the boat harbor. There may be 12 or so. The martins are nesting in pilings at the marina. There are 5 eBird reports of martins there this year, between 2 and 12 birds from April 25 thru June 10, plus the OBOL report.

I strongly encourage anyone who can make a trip there to look for this very rare phenomenon and further document it. Photographs would be extremely valuable.

To the best of my knowledge, this has never before been documented for Western martins.

Please let me know what you find. Photographs would be extremely valuable.

Stan Kostka

lynnandstan at earthlink.net <http://earthlink.net/>

Arlington WA

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