Lake Merced nesting birds and eco problems


Dan Murphy <murphsf@...>
 

Hi,

I spent some time at Lake Merced yesterday, 6/11.

Of the 6 Great Blue Heron nests it seems the young have fledged from 3
and are about ready to fly from the other 3. If they weren't lost, this
was a pretty good year with as many as 15 young being fledged.

There were at least 70 Double-crested Cormorant nests in the colony by
the police gun range. Most had young. I didn't count nests at the
other colony, but there are about 15.

Swallows seems way down in numbers. I checked the Cliff Swallow colony
on the concrete bridge at the south end of the lake. There were only 12
nests. That is down from 38 nests in 1999 and 1998, and down from 49 in
1997. There were at least 5 freshly broken nests and others which may
have been destroyed early in the season. In any case, it looks like
Cliff Swallows are having a disasterous nesting year. We could loose
this species at LM since SFSU seems finally to have removed the colony
which used to be on the west wall of the library. Other swallow numbers
are down as well. We should be seeing large numbers of swallows feeding
over the marshes and open waters of the lake, but they just aren't
there. Who knows?

I heard a Downy Woodpecker drumming at the north end of the lake. It
sounded like spring. I can't remember hearing them drumming so actively
this late in the season. About an hour later Joan an I took a walk from
the circle through the golf course and back around. As we walked along
Lake Merced Blvd. by that huge eucalyptus grove I found Rec and Park is
cutting large numbers of eucalyptus branches. This is right in the area
of the Tree Swallow nesting site and near where the woodpecker was
drumming. Though I don't mind general tree trimming, I take issue with
it during the nesting season. I'd be really interested in knowing how
many nests have been destroyed by this project. Think about it. We
have Tree and Violet-green Swallow, Downy Woodpecker, Pygmy Nuthatch,
Brown Creeper, Red-shouldered Hawk, Robin and God knows what else at the
end of their nesting cycle and the tree hackers can't wait to chop them
out of their nests.

Actually this is a serious management problem since the Rec and Park
Department and Commission don't seem to acknowledge birds have any level
of protection at all. Remember the commission approved the removal of
trees near the Boathouse several years ago although they knew there were
active Tree Swallow and Pygmy Nuthatch nests in the trees scheduled for
removal. Of course they wanted to provide parking for customers of the
Boathouse. And remember too Rec and Park has been trimming trees at Mt.
Davidson during the nesting season. I'm sure it's going on elsewhere as
well. Just a little thought for you the next time you think about
what's going on in your favorite park.

Well, enough of this ranting and raving.

Best, Dan

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