Breeding Biology
Redpolls breed in mixed birch or conifer forests often in loose
associations with other Redpolls. The female builds a cup nest of small
twigs, grass and plant stems, often high in a tree. From 3 to 7 pale blue
eggs marked with fine pink or lilac spots are incubated by the female and
hatch in 10 to 13 days. Both parents tend the young, who leave the nest in
another 11 to 14 days.
Banding Recoveries
The records at the Bird Banding Laboratory show that between 1955 and
2000, 342,158 Common Redpolls and 11,732 Hoary Redpolls were banded and
released. Of these, 698 Common Redpolls and 27 Hoary Redpolls were
encountered at locations away from where they were banded. Banding studies
show that Redpolls live up to 8 years in the wild.
If you should recover a banded Redpoll, please report the band number to
the Bird Banding Lab by calling 1-800-327-BAND. Your report will add
valuable information to what is known about this species.
Frequently Asked Questions
1. How do these tiny Redpolls and other small Arctic birds survive
winters?
Redpolls live in high Arctic regions where winter darkness lasts up to 6
months and temperatures plunge well below freezing. Research has shown that
Redpolls are able to survive temperatures down to minus 67 degrees C (89
degrees F below zero).
How do these little birds survive these harsh conditions? Redpolls have
anatomical, physiological and behavioral adaptations that enable them to
survive and to thrive in these harsh winter conditions.
One of the most important anatomical adaptations that allow Redpolls to
thrive in severe cold weather is their esophageal diverticulum, a partially
bi-lobed pocket situated in their neck. Redpolls use the esophageal
diverticulum to store seeds, especially before nightfall or before a storm.
The extra seeds allow them to “feed” while sheltering from the cold. The
birds knock seeds from trees, gather the seeds from the ground and store
them in the esophageal diverticulum. They then fly to a sheltered spot where
they can regurgitate, shell, and consume the seeds at leisure while
protected from predators and harsh weather conditions.
Behavioral adaptations are also important. Redpolls, as do other species
of birds, can fluff their contour feathers to trap layers of air to insulate
their body and greatly reduce heat loss. Redpolls will sometimes burrow into
the snow to escape especially cold weather. Under the snow, temperatures
will remain at about minus 4 degrees C (24 F) even when air temperatures
drop to 45 degrees C below zero (-49 F).
2. Why do northern finches come south during some winters and not
others?
Every couple of years or so, northern finches invade more southerly
locations. These invasions, also called irruptions, are greatly anticipated
by bird watchers as species that normally occur at high latitudes move south
in large numbers. It is generally agreed that these irruptions are triggered
by shortages of food in the normal ranges of these species of birds.
Synchronous failures of northern trees to produce enough seeds to support
populations of seed eating birds causes these birds to move southward in
search of food. Seed failures and the resulting invasions of seed eating
birds occur simultaneously in North America and in Europe.
In North America, several species of finches tend to invade during the
same years. These include the Pine Siskin, White-winged Crossbill, Purple
Finch, Pine Grosbeak, Evening Grosbeak and the Redpolls. Other seed eating
species, such as the Red-breasted Nuthatch, will also come south in invasion
years.
In Europe and Asia, Nutcrackers, Jays, Owls, the Great Spotted
Woodpecker, Brambling, Great Tit, Coal Tit, and the Willow Tit also show
irruptive behavior patterns.
3. What do Redpolls eat?
Birch seeds are the staple food for Redpolls most of the year. During
the winter, Redpolls also consume seeds of Alders, willows, pines, elms,
basswood, larch, and seeds from many species of weeds. Insects are an
important part of their diet in the summer, especially during the breeding
season.
4. How can I attract Redpolls to my feeders?
Redpolls will readily come to feeders where thistle seeds are offered.
In fact, the Genus name Carduelis for this group of birds comes from the
Latin Carduus meaning “Thistle.” Well-stocked feeding stations that attract
finches will most likely attract Redpolls.
5. How are the different species of Redpolls related?
Worldwide, several subspecies or races of Common Redpoll are recognized:
These include the Common Redpoll (sometimes called the Mealy Redpoll), (C.
f. flammea), the Lesser Redpoll (C. f. cabaret), the Greater Common (or
Greenland) Redpoll of Greenland and Baffin Island (C. f. rostrata), and the
Redpoll of Iceland (C. f. islandica).
In the Palearctic, (Europe and Asia), the Lesser Redpoll occurs from the
UK through central Europe. The Mealy Redpoll, a pale gray race, occurs from
Scandanavia eastward across northern Russia. C. f. rostrata, a larger, more
heavily streaked, dark brownish race, occurs in Greenland and Baffin Island
with winter range extensions into Iceland and the British Isles (Beaman and
Madge. 1998).
In the Nearctic (North America), the Common Redpoll (C. f. flammea)
breeds from Alaska to Newfoundland and may winter south from California
across to Virginia. C. f. rostrata breeds in the Northwest Territories and
may winter south from Colorado across to New Jersey.
Some taxonomists suggest that the Redpolls are just one species with
several subspecies. Others suggest that there may be as many as 6 separate
species.
The Arctic Redpoll, a separate species, is a frosty looking version of
the Common Redpoll. In North America, two subspecies are recognized. C. h.
hornemanni breeds in the Northwest Territories and may winter south from
Michigan to Maryland. C. h. exilipes breeds from Alaska to Labrador and may
winter south from Oregon to Maryland. Intermediates between Common and Hoary
Redpolls occur. For this reason, a Hoary Redpoll in a flock of Common
Redpolls should be identified with caution and may not be safely separated
in the field or even in the hand (Pyle 1997).
Photo Credits
Special thanks go to Brad Baumgardner, Interpretive Naturalist, Indiana
Dunes State Park, John Schaust, Chief Naturalist for Wild Birds Unlimited,
and John Spicer for kindly allowing us the use of their respective
photographs for this Common Redpoll site.
Further Reading
Alderfer, J., Ed. 2006. Complete Birds of North America. National
Geographic. Washington, DC.664 Pp.
Beaman, Mark and Steve Madge. 1998. The Handbook of Bird Identification
for Europe and the Western Palearctic. Princeton University Press,
Princeton, NJ. 868 Pp.
Baicich, P. J. and C. J. O. Harrison. 1997. A Guide to the Nests, Eggs,
and Nestlings of North American Birds. 2nd Ed. Academic Press, Boston. 347
Pp.
Baughman, M. ed. Reference Atlas to the Birds of North America. National
Geographic. 480 Pp.
Ehrlich, Paul R., D. S. Dobkin, D. Wheye, and S. L. Pimm. 1994. The
Birdwatcher’s Handbook. A Guide to the Natural History of the Birds of
Britain and Europe. Oxford University Press. Oxford. 660 Pp.
Flint, V. E., R. L. Boehme, Y. V. Kostin, and A. A. Kuzenetsov. 1984. A
Field Guide to Birds of the USSR. Princeton University Press, Princeton, NJ.
353 Pp.
Jonsson, L. 1993. Birds of Europe with North Africa and the Middle East.
Princeton University Press. Princeton, NJ. 559 Pp.
Pyle, P. 1997. Identification Guide to North American Birds. Part I.
Slate Creek Press, Bolinas, CA. 731 Pp.
Terres, J. K. 1995. The National Audubon Society Encyclopedia of North
American Birds. Wings Books, NY. 1,109 Pp.
Back to Top | Back to Bird
Photos Menu
All images are courtesy of CWBO. All image copyrights are owned by CWBO.
Any use of these images must have permission of CWBO. |
