| The previous lessons on providing lots of
ventilation and oversized roofs to keep a birdhouse cool might seem
counterproductive in the early spring when cold weather threatens nesting
birds, especially if you live in North Dakota, Michigan, or any of the
other more northern states.
But, in early spring when temperatures plunge to
twenty degrees or below the female bird will keep the eggs and nestlings
warm by sitting on them. Therefore, the greatest heat loss
experienced by the eggs or chicks comes from below them, not above.
A nest box with a thick wooden bottom, thick sides and ample nesting
material aids the female bird in keeping the eggs and chicks sufficiently
warm.
If temperatures fall to twenty degrees or lower
before incubation begins, the eggs will be lost, even if there is no
ventilation.
Further, cold weather is not normally the fatal
factor when nests fail early in the spring. Wet nests and lack of
insects to feed the young chicks are far greater problems.
And, if extremely cold weather in early spring does
cause the nest to fail, the birds will normally build a second nest and
begin anew and little is lost.
But, because all States experience temperatures of 90
degrees or higher in the most productive part of the birds' breeding
season, providing a birdhouse that stays cool and dry is far more
important than protection from cold.
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