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Nestbox
Program at the
San Joaquin Wildlife Sanctuary
in
Irvine
by
Christine Tischer
SJWS Nestbox Program Manager
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. . . . . . . . . .photo
by Trude Hurd |
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| History |
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| The
nestbox program started as a mere handful of boxes
at the San Joaquin Wildlife Sanctuary in the late
90’s. It was established as a joint program
between Irvine Ranch Water District (IRWD) and Sea
and Sage Audubon. IRWD installed the boxes as part
of a mitigation requirement for their water reclamation
plant. Sea and Sage Audubon provides the expertise
of several volunteers to monitor and maintain the
boxes. Monitoring of the boxes began in the year
2000. Hardly any vegetation was associated with
the ponds at the start of the program in 2000. Since
that time, restoration activities have greatly improved
the landscape at the marsh while providing more
foraging, overwintering, and nesting habitat for
numerous bird species. Boxes are shifted on a yearly
basis to account for vegetative growth and to optimize
productivity. |
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| Monitoring |
| Volunteers monitor
the boxes on a weekly basis during the breeding season (March
through July). They count the number of nests, eggs, chicks,
and number of chicks that fledge (successfully leave the nest).
They also ensure that boxes are in workable condition, trim
vegetation from around the boxes, protect the birds from ants,
mites, and other predators, and record banding information.
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Christine
Tischer opening Tree Swallow nestbox |
Tree Swallow nestbox |
Tree
Swallow fledgling |
photos
by Trude Hurd |
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| Banding
Program |
| The majority of
Tree Swallow chicks were banded as part of the Tree Swallow
Nesting Project, a Ventura-based non-profit organization. Chicks
are banded at 10 days of age and fledge between 21 and 28 days
of age. A small aluminum band is placed around one leg of each
bird by a certified bander. Each band is engraved with a unique
series of numbers, typically 4 numbers in the top row and 5
numbers in the bottom row. The band numbers, age of bird when
banded, and banding location are reported to the U.S. Geological
Survey (USGS), who then inputs the information into a nationwide
database for banded birds. Valuable information can be collected
when birds are found or recaptured later in life. If you ever
find a banded bird, record the band sequence from top to bottom
and from left to right. Note the leg the band is on, and whether
it’s the bird’s left or right leg. Some birds can
be color banded with one color band, multiple color bands, or
a combination of color and metal bands. Again, note the leg
it occurs on and the sequence of the color bands from closest
to the body to furthest from the body (for example, blue over
red or metal over yellow). Don’t forget to note the type
of bird if you are able to identify it or at least a description
of the bird and its size. This information can be called into
the USGS Bird Banding Hotline at 1-800-327-BAND. You will receive
an official certificate in the mail describing where and when
the bird was banded and you’ll be providing invaluable
data for that bird species. |
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| 2000-2009
Nestbox Results |
| Although the nestboxes
are appropriately sized for a number of cavity-nesting bird
species, the boxes are used almost exclusively by Tree Swallows
(Tachycinita bicolor). According to the Atlas of Breeding Birds,
Orange County, California (Gallagher, 1997), no successful Tree
Swallow nesting was confirmed during atlasing years (1985-1990).
Tree Swallows typically nest in tree cavities as indicated by
their name. However, this species and other cavity nesting species
were on the decline as breeding birds in Orange County because
of the loss of old growth tree groves to residential and commercial
development. Luckily, Tree Swallows readily adapt to artificial
nestboxes. Unlike Tree Swallows on the east coast that are known
to have only one brood per season, Tree Swallows in southern
California can have two broods in a single nesting season. The
number of second broods is typically lower and can likely be
linked to a number of factors including weather, food availability,
and 1st brood nest failure/success to name a few. The
program has been highly successful in bringing theTree Swallow
back to the County of Orange as a breeding bird species In addition
to Tree Swallows, a few Western Bluebirds (Sialia mexicana)
and House Wrens (Troglodytes aedon) have claimed a box or two
over the years. The results of the ten nesting seasons
from years 2000 to 2009 are summarized below. |
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| Nestbox
Availability and Utilization |
| The program has
increased from 56 boxes in 2000 to a high of 113 boxes in 2004
and presently supports 87 boxes. The graph below shows the number
of nestboxes available each year (dark blue line) compared to
the number of nestboxes utilized during each nesting attempt.
A box was considered utilized if at least one egg was laid in
the nest. The graph below includes all bird species that claimed
a nestbox, not just Tree Swallows. Year 2002 marked the first
year that a bird species other than a Tree Swallow attempted
to nest. Two pairs of Western Bluebirds (Sialia mexicana) and
one pair of House Wrens (Troglodytes aedon) occupied three boxes
during the first nesting period. In 2003, one pair of bluebirds
successfully nested and fledged 3 young during the first nesting
period. Two pairs of House Wrens and one pair of Western Bluebirds
occupied three boxes during the first nesting period in 2008.
One box supported a pair of House Wrens during the first nesting
period and Tree Swallows during the second nesting period in
2009. |
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| Nestbox
Availability and Utilization |
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photo
by Trude Hurd |
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photo
by Trude Hurd |
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| If
you are interested in helping out with this program at the San
Joaquin Wildlife Sanctuary, please contact Christine Tischer
at
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| To
learn more
about the Tree Swallow Nesting Project, visit http://www.treeswallows.org
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