Habitat 2000 / Learning About Wildlife
The great blue heron, one of our largest, most picturesque
avian migrants, stands more than a metre tall. It breeds from
March to May throughout southern Canada after trekking 3,000
to 4,000 kilometres from Texas, Florida, Mexico, or South
America. Herons typically nest in treetop colonies of 20 to
40 birds on islands, peninsulas, shorelines, and beaver ponds.
They abandon these sites as nesting trees rot and fall to
the ground.
You can slow or halt a colony's decline. Guard nests in living
trees from beavers by wrapping sheet metal around the bases
of trunks to prevent them from being felled. Replace collapsed
trees with nesting platforms to greatly extend the life of
a colony. The following nesting structure will accommodate
not only great blue herons but also black-crowned night-herons
and double-crested cormorants.
- Choose a site in an existing colony, with water no more
that 1.5 m deep. Erect nesting structures from January to
March, before herons return from their wintering grounds.
- Obtain new or used cedar utility poles (30' long and 8
to 10" inches in diameter at the base) from your local hydro
or telephone company.
- Construct three nesting platforms for each pole. Cut the
materials, drill the bolt holes, and assemble the platforms
before going to the project site.
- Nail the outer nest support (A) to the short support brace
(B) and the long support brace (C), with a 53-cm distance
between nailing points. One end of the outer nest support
(A) will extend beyond the short support brace (B) to serve
as a perch. The long support brace (C) will extend beyond
the outer nest support (A) to serve as another perch. Nail
the inner nest supports (D, E, and F) to the support braces
(B and C).
- Bolt one side arm (G) to the long support brace (C). Bolt
the other side arm (H) to the short support brace (B).
- Finish the construction on the ice at the project site.
(Ensure student safety by getting assistance from parks
staff, a local conservation group, or utility company.)
Attach support braces (B and C) and side arms (G and H)
to the pole (I) with lag bolts. Give each platform an upward
tilt to create a nesting niche.
- Place the first platform at the top of the pole, the second
1.2 m below, and the third 1.2 m below the second. Project
the second platform in the opposite direction to the first
and third. Wire a few branches to the top of each platform.
- Use a chain saw to cut a hole, 60 cm in diameter, in the
ice.
- Drill a hole 2 m deep in the earth with a 20-cm power
auger. Set the pole firmly in the hole.
- Inspect the structure for damage at the end of each nesting
season.
Materials (sold in imperial measures)
A 1" x 2" x 40" E 1" x
1" x 19"
B 2" x 2" x 30" F 1" x
1" x 18"
C 2" x 2" x 7' G/H 1" x
2" x 27"
D 1" x 1" x 20" I 30'
long x 8 to 10"
in diameter
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