[obol] Eucalyptus and birds

[Wayne Weber]

Dan,

 

When you are speaking about "Eucalyptus", I presume you are speaking about
Tasmanian blue gum (Eucalyptus globulus), which is invasive in California.
Am I correct?  At times, it sounds like you are

speaking about all species of Eucalyptus. As this is a large genus (about
450 species, I believe), it seems unlikely that your comments apply to all
species. The California Invasive Plant Inventory lists only one species of
Eucalyptus other than blue gum as being invasive in that state.

 

Can you cite a couple of published references for the effects on birds that
you mention?

 

Many thanks,

 

Wayne C. Weber

Delta, BC

contopus at telus.net

 

 

 

From: obol-bounces at lists.oregonstate.edu
[mailto:obol-bounces at lists.oregonstate.edu] On Behalf Of Dan Gleason
Sent: February-04-08 3:53 PM
To: LammergeierEyes at aol.com
Cc: OBOL 
Subject: [obol] Eucalyptus (was Re: let's wage a dialogue not a war)

 

I would like to point out the Eucalyptus are NOT good for migrating
warblers. Eucalyptus trees exude a sticky gum, which is partly why some
species nearly explode in a fire. These are fire-adapted plants and depend
upon the fires they fuel for seed dispersal. Birds, such as honey-eaters and
leaf-gleaners that co-evolved with Eucalyptus trees have long curved bills
that they can probe into flowers and avoid the sticky resin. The North
American kinglets, vireos and warblers have short straight bills. They are
attracted to Eucalyptus flowers and the insects housed within. However, the
short length of their bills means that they must probe deeply into the
flowers to obtain insects. In doing so, their faces are often covered with
this sticky resin. For some birds, the resin is think enough that it can
become difficult to open the mouth, in others, their nostrils become
plugged. A great many of these birds will suffocate and die each year.
Additionally, birds such as Anna's Hummingbirds will build nests in these
trees but as many as 50% are blown out by winds whereas in the shelter of
native plants, only 10% of the nests may be lost. Great Horned Owls and
Red-shouldered Hawks do seem to utilize the trees successfully for nesting
but most native bird have less overall success in eucalyptus.

Ground-nesting and ground-foraging birds are also put at risk in groves of
Eucalyptus. The litter from these trees can be as thin as 3-4 feet in some
areas. The insects and micro flora and fauna and other organisms that
naturally break down this debris in Australia are not found here. All but a
few native plants (poison-oak being one of the survivors) are choked out or
poisoned by the chemicals from the Eucalyptus, leaving an area of desolation
unfit for a healthy diversity of native birds.

These are definitely not bird-friendly plants for North American species.

Dan Gleason

-------------

Dan Gleason

dan-gleason at comcast.net

541 345-0450





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