Winter is a difficult time for many birds, especially for small birds like the Pine Siskin, Cardulis pinus, a small finch. These are very social birds and congregate sporadically in dense flocks around backyard feeders in North America and the United Kingdom.
The problem of Salmonellosis
Birdseed itself is not believed to be the initial source of the bacteria, salmonellosis, which is a bacterium that plagues the Pine Siskin. Such infections have increased drastically since 1988 (1) so it is definitely a problem to be reckoned with wherever, and whenever, Pine Siskins make stop-overs along their migratory routes.
What to look for
You usually find sick finches in the vicinity of feeders. They appear fluffed up, reluctant to fly, they appear to be breathing heavily; and they look as if they are having difficulty swallowing. Damage to the gullet from salmonellosis is so severe that it causes a partial blockage, preventing food from getting to the bird’s stomach even as it continues to eat. In advance stages of infection you will see mucus sprinkled with Nyjer seed accumulating around their beaks, and over-extended crops.
Death from starvation in such cases in imminent.
Cases of salmonellosis are also reported in domestic cats that prey on sick birds around bird feeders. So any wildlife that consumes an infected bird is also at risk for this infection.
When finches congregate at feeding stations [which happens year-round as they migrate to ever-new food sources] a general build up of bacteria occurs, contaminating the food and water, feeders, as well as the ground beneath feeders.
What you can do
You can help prevent a build-up of potentially lethal bacteria at your feeding stations through weekly cleaning and routine disinfection of bird tables, feeders and drinkers. The areas beneath the feeders can also quickly become contaminated and should be kept as clean as possible, with any uneaten food removed on a routine basis.
Careful observation of your feeding stations is vital. Especially in winter months when late afternoon temperatures drop precipitously, you will see fluffed up finches still hanging around feeders long after the rest of the flock have gone to roost. They don’t have the energy to catch up with their peers, or even to fly up into the protective branches of evergreens. They are also starving (literally) because they cannot digest the food they eat.
As darkness falls they can be found hugging the foundation of the house or other structure at the ground level, or holed up in a masonry crack near the ground. You will even find them hugging the base of garage doors or in piles of leaves in corners of buildings with their heads tucked under their wings.
Not only are they sick but also they are freezing cold at this point and, without intervention, they will surely freeze to death. In bitter cold weather we walk around the house and the deck with flashlights at dusk on those days when we know there are sick finches at our feeders; and some days we retrieve 7 or 8 Pine Siskins (or more) over the course of an hour and bring them into the heated garage to die in peace and warmth in small containers we keep for this purpose. During especially cold stretches we search for stragglers later on in the evening as well. By morning most will be dead, and some even die in our hands as we are preparing a warm enclosure for them. Some will last 2 days…but not often.
Death occurs from advanced starvation. You will observe a general shutdown with tell-tale labored breathing, discolored droppings and accumulated feces on the underside. Finches with slightly less advanced infections will attack or bully the sicker ones, so we try to keep the weaker juveniles isolated.
We encourage you to do the same. Not only is this the humane thing to do but it helps cull the sick ones and keeps them from constantly reinfecting your feeding stations.
If your feeders are suddenly inundated by Pine Siskins, reduce the number of Nyjer feeders and step up environmental cleaning routines, otherwise even Goldfinches (Carduelis tristis) will fall victim to the Salmonellosis infection. Walk around your yard during heavy infestations, for you may find dead Pine Siskins on the ground and you need to remove them.
Be careful to wash your hands thoroughly after every such encounter and before you interact with any household pets.
Feeding birds may become a necessity
Note this comment from a member of the Florida Native Plant Society (5): “Biologists are worried that climate change may change rain patterns – timing and/or amounts – so that plants fruit weeks earlier or later. As a result, migrating birds who time their flight to coincide with certain fruits, seeds and/or insects being available en route may find their customary food supply unavailable. If they do not put on enough fat before they make their trip to tropical America, they may starve before they get there. So it’s possible that feeding birds will become a necessity for their survival, not just an option.”
Not all birdfeeders are safe. Many birdfeeder designs on the market are unsuitable for birds and they may even be harmful. Avoid the cutesy little feeders that don’t open easily for cleaning, which accounts for 80% of the feeders available in tractor supply stores, hardware stores and popular discount stores. Particularly avoid feeders made of metal that will rust.
You get what you pay for in birdfeeders. Do the birds a favor and buy premium birdfeeders from reputable stores like WILD BIRDS UNLIMITED or from Duncraft Birds (2) on the Internet. Look closely to see how a feeder is made. For many of the better feeders you can also get a large plastic dome that slips down over the top of the feeder to help protect seed from getting wet from rain or snow. The bigger the dome the better.
You should weekly dismantle and clorox any feeders that you are using. Take the feeder totally apart. In between washings shake your seed feeders before refilling to dislodge compacted seed and dump out any wet clumps of old seed into a trash bag.
Use this disinfectant solution: 1 part bleach to 10 parts water, then rinse and allow feeders to dry before refilling with seed.
Mold is a killer. Never feed birds stale or moldy foods. Such food is a breeding ground for salmonella and can cause food poisoning. If you do put out bread or chips or peanuts, check daily for signs of mold and pick up and trash any food that has not been consumed by dark. Clorox will NOT kill mold and once it infects your deck or feeders you will have to use MOLDSTAT or a similar EPA-registered pesticide to kill it.
The greatest challenge for healthy birds is staying warm
To keep warm, birds must consume large amounts of calories that are then metabolized to provide energy and body heat. Small songbirds eat continuously during the short daylight hours of winter to maintain their body temperature. At night, they lower their body temperature to conserve energy.
Most non-migrating birds fill their crops before nightfall to boost their caloric intake during the night. The availability of food, therefore, has a lot to do with a bird’s chances of survival during long, cold winter nights.
You can aid birds in winter by providing high quality foods that contain lots of oils and fats such as suet (3), black oil sunflower seeds, peanuts and nuts, cracked corn, seed mixed with millet, and Nyjer seed which is extremely rich in oils.
You can buy bags of peanuts in the shell and crunch them before putting them out for the birds on a large plastic platter. It is cheaper this way and the birds seem to like foraging for the peanuts, and I think they even enjoy the shell fragments. It is a highly sought-after cold weather treat! Remove the peanuts at the end of the day to prevent mold from developing.
Be sure to also provide a heated water source during cold weather, one that is certified for outdoor use. Scrub and bleach it regularly. You will enjoy watching the antics at the de-iced ‘spa’ that you provide!
Warn birds away from window collisions
When you place feeders around large expanses of glass it is also important to also place ultraviolet decals on the outside of the windows to help prevent window collisions. Duncraft Birds (4) has some excellent window strike solutions and they do work. They need to be replaced approximately every six months, however, as they fade in bright sunlight and loose their effectiveness.
Providing cover for birds is also important
Natural plant covers can aid birds seeking protection from cold weather. By providing evergreen trees and shrubs you can offer a safe place for birds to escape the elements. Native plants attract a greater diversity of songbirds and often in greater numbers as well. The flowers, foliage, leaf litter, etc. of native species also attract insects that the birds will feed on. Besides, native species of plants are better for the environment overall.
Additionally, you can arrange piles of logs and tree debris, including cut evergreen limbs, to create hiding places. Stacked cords of wood with tarps also provide excellent cover.
Don’t prune shrubs in winter! Yes, winter is the recommended time to prune but over-grown shrubs serve as warm lodging for many species of birds. Wait to prune until warmer weather arrives.
Roosting boxes that are constantly available year-round are more readily used come springtime nesting season.
A roosting box configured for winter should have the entry hole near the bottom of the box to keep as much heat inside the box as possible because heat rises. In a well-designed box, the door can then be reversed in the spring so that the hole is near the top to help contain baby birds.
In winter fill the roosting box with cedar chips and add a few temporary perches higher up so that birds can make use of all the space inside the box. But be sure to remove these come Spring.
Wood such as bald-cypress or cedar is recommended, and the box should be strong, weatherproof, securely fastened, and facing a southern exposure away from noise and activity.
Avoid treating the inside of the box with stains or preservatives whose fumes can be harmful, and also don’t forget to clean them out occasionally!
Birds face ever-increasing threats in our urban world and the least we can do is give them a fighting chance. Don’t be the typical person who puts out a feeder or two and forgets them. Be responsible and provide a safe feeding environment. Learn about the birds that come your way and try to accommodate their critical cold weather needs.
Your efforts will be richly rewarded!
(3) The basic recipe for bird feeder suet: mix together 1 cup melted suet, 1 cup peanut butter and 6 cups cornmeal. Possible additions include seeds, olive oil, nuts or raisins. Pack into a mold to cool and set.
(5) Jan Alyn of The Florida Native Plant Society; snow flurries are not out of the question this winter, even in Tampa Bay!
About the Author:
Dr. Rudolph is a member of the Smoky Mountain Animal Care Foundation Board of Directors in East Tennessee. She is also an experienced wildlife rehabilitator and was long-time president of the Williamsburg Area S.P.C.A. Board of Directors in Williamsburg, VA [1979-1992]; and a past president of the Virginia Federation of Humane Societies. You can find out more about her at www.drellenrudolph.com
This material may not be published, broadcast, rewritten, or redistributed. © 2010 Dr. Ellen K. Rudolph. All rights reserved.