Nest Type: Cup
Nest Location: Deciduous
tree, shrubs; 2-8'
Clutch Size: 4-5
Food: Insects, seeds
The Rusty Blackbird has
a relatively large breeding distribution primarily confined to the boreal
zone of Canada. In Minnesota, the species is a rare nesting bird in
northern Cook, Lake, and St. Louis Counties (Janssen 1987). The species
is a common spring migrant in Minnesota and a a relatively common fall
migrant. The spring migration period is generally from mid-March through
mid-May, with most migrants occurring during the month of April. Fall
migration is from early September through early December, with most
of the migrants being found in the month of October. The species occasionally
occurs as a winter visitant in the southern portion of the state (Janssen
1987). Rusty Blackbirds winter in the southern U.S., and are usually
found in or near bottomlands.
On the breeding grounds,
the species is almost always found associated with water such as woodland
ponds, bogs, flooded lakes, stream edges, or habitat created by beaver
dams (Kennard 1920, Bent 1958, Erskine 1977, Brewer et al. 1991). Hence,
the species was classified as a riparian associated species. Brewer
et al. (1991) noted that its territories seem to be rather large because
nest sites are generally separated by .8 km or more.
The Rusty Blackbird generally
constructs its nest in dense undergrowth of evergreens, but deciduous
shrub vegetation is also used, usually in association with water. The
nest is generally less than 10 ft above ground, and 4-5 eggs are typically
laid (DeGraaf et al. 1991). The species is highly omnivorous and will
forage on insects, seeds, grains, and fruit, depending on availability
(Martin et al. 1951). During the summer the diet is more insectivorous,
while in the winter more grains and fruits are taken.
In Minnesota, no information
is available on general population trends of the species because of
its rarity. The species has likely always been relatively rare in Minnesota
because its primary breeding habitat is farther north throughout Canada.
However, because the species is associated with water edges created
by beaver dams, it may have been more common in the past. It is unlikely
that forest harvesting or management on the breeding grounds had a major
effect on the species. Reductions in beaver populations and development
of lakeshore property have likely had a greater effect on the species