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Photo by Tom Grey

All About Bird Feeders

All About Bird Feeders

by Garth Harwood

A recent bulletin from the Cornell Lab of Ornithology (CLO) reports that a whopping 43% of U. S. households now feed wild birds. And I know from my perch in the SCVAS office that it's much the same story here in Santa Clara County.

Questions regarding bird-feeding make up a large part of the inquiries I receive from the public. The questions range from the obvious (What sort of seed mix should I buy for my finches?) to the not-so-obvious (Will I attract cowbirds if I leave seed feeders up all summer?). It's also true that winter is the time when our bird-feeding practices have the most potential to help — or harm — wild birds (see section on winter feeding below). So, as this El Niño winter gets underway, it seems like a good time to review the basics of local bird-feeding as well as some ideas for expanding the number and variety of birds at your feeders.

Research into the subject has revealed that the bulk of most wild birds' diet is ordinarily gathered from natural sources, even when feeders are continuously available. Moreover, in our immediate area, the relatively mild climate is easier on birds, so that the provision of extra feed is seldom a matter of life and death. Still, the presence of many feeders offering a range of food types may help maintain a more diverse and abundant bird community, especially in our most urbanized areas, and our feeders can provide an important safety net as well. In our individual homes and gardens, the ultimate importance of bird-feeding may well be greater for ourselves, as we get to know the birds on a much closer and more "personal" level.

Types of Feeders

There are several general categories of bird feeding devices to choose from; and, generally speaking, a satisfying diversity of birds can best be attracted by maintaining one or more feeders from each category.

Tube feeder
Tube feeder

Seed Feeders. In three basic shapes, these are the most popular feeders, and at least at our office, they keep a crowd of eager birds (mostly House Finches) close by from dawn to dusk. "Tube" feeders are columnar in shape and typically have four or more perches for small to medium-sized songbirds. They are very popular with chickadees, titmice, and especially finches. Jays, blackbirds, and other big birds find them awkward and tend to avoid them. "Hopper" feeders permit larger birds ready access, and are placed on trees or posts to attract larger, tree-loving species such as jays. And "tray" feeders are often placed near the ground to bring in the ground-feeders such as doves, towhees, and sparrows (although these species are often content to simply scavenge the overspill from other feeder types up above). For a breakdown of the main seed types available and the birds attracted by each, see the table below.

Window mount feeder
Window mount feeder

Suet Feeders. Wire baskets or nylon bags are used to hold cakes of rendered animal fat. Commercially produced cakes are usually loaded up with seeds, bits of fruit, or other favorite bird foods. They are surprisingly tidy, odorless, and attract a greater diversity of birds than any other feeder type at our office. Any given day, ours is visited by Chestnut-backed Chickadees, White-breasted Nuthatches, Nuttall's Woodpeckers, Oak Titmice, and a jay or two. On rarer occasions, we have observed Black-headed Grosbeaks, Red-breasted Nuthatches, Acorn Woodpeckers, Song Sparrows, and White-crowned Sparrows at it as well.

Suet feeder
Suet feeder

I often speak to people who tell me that they've given up on suet because "I put out a cake months ago and nothing ever came." That's a shame, because the constant parade of birds at ours is one of the great rewards of working here at Audubon. Those disappointing experiences are most likely the result of a "turned" suet cake that repels, rather than attracts the birds.

Suet easily turns rancid in hot weather, so it is often considered a winter food. I keep it up year-round at our office, however, because the birds love it. By using suet "dough", formulated especially for summer use, we avoid the problem of turned cakes. (If your experiment with suet met the same fate mentioned above, try removing the offending cake, washing the basket thoroughly, and placing a fresh cake in it in a new location. Give the birds 3 or 4 weeks to catch on to the new resource.)

Nectar feeder
Nectar feeder

Nectar Feeders. There are numerous styles available, too many by far to review them all here. Suffice it to say that the primary considerations are capacity and ease of cleaning. We recommend feeders of relatively small capacity for hummingbirds, because it encourages regular cleaning. Nectar (standard recipe: 1 part sugar for every 4 parts water), ferments quickly, especially in full sun, with negative health effects on the birds. No color is needed in the nectar, as the bright parts of the feeder will do all the attracting that needs to be done, without any risk of chemical contamination. It's best to clean your nectar feeders at least once a week in warm weather with a bottle brush (seed feeders can be done much less frequently unless you see diseased birds using them).

Orioles are increasingly common summer migrants to our area and will become regular visitors at a nectar feeder if they can get at the stuff. As heavier birds, they prefer to eat while perched, so oriole feeders with perches are a great addition to your array of feeders from the second half of March through August.

Natural Sustenance

Food Plants. Plants which provide food to birds are of special importance to any successful arrangement of conventional feeders. In addition to their food value, they provide protective cover, resting places, nesting sites, and crucial "observation posts" for territorial species such as hummingbirds. They also harbor insects, which will provide still another supplemental food source. Like people, birds appreciate variety in their diets, so your yard will be more popular with the birds if it has an appealing variety of goodies such as berries (winter-ripening varieties are best), trumpet-shaped flowers for the hummers, and a fruit tree or two. It's amazing how many Cedar Waxwings a tree full of persimmons can hold!

Water. This essential should never be overlooked, and although it may be overabundant this winter, it's a good idea to have a source ready for any dry spells during the year. Even if a natural source exists nearby, your clean "birdbath" may spare your local birds having to drink from sources of dubious healthfulness such as roadside puddles. Speaking of water, you'd be surprised how often I hear from people whose water sources have turned into "feeders" in their own right. Herons and egrets are especially adaptable when it comes to fishing for somebody's prized koi goldfish in a backyard pond. If you have that exotic problem, incidentally, the experts recommend stringing fishing line in parallel strands a couple of feet over the pond every 18-24 inches in a grid pattern.

What to Feed, and When

In our area, almost every type of feed is suitable for year-round use, with several special considerations and exceptions. Many experts think it's a good idea to cease feeding millet and similar grains during the height of the breeding season, because it is suspected in promoting local concentrations of the parasitic Brown-headed Cowbird and the aggressive, non-native House (AKA "English") Sparrow. That's certainly possible, judging by the birds I've seen at the Audubon feeders. The solution is to switch to any combination of sunflower seed, thistle, suet dough, etc., since these species largely avoid them, while other feeder visitors such as finches like one or more of the alternatives just as well. Alternatively, it does no harm to cease your feeding supplements in the summer, as other food resources are abundant then. (So yes, you can enjoy a guilt-free vacation).

In winter, it's a good idea to adjust your offerings toward a higher fat and oil content (see following section). Keep hummingbird feeders up, but take down your oriole feeder. Thistle feeders will be more popular in winter, when Pine Siskins and American Goldfinches return from their breeding grounds to join the Lesser Goldfinches that are the most common summer thistle-feeder.

Feeder Placement, Predation, and Disease Prevention

Sometimes birds simply refuse to approach a feeder, no matter what's offered, leaving its owner perplexed. What could they have done differently?

The answer frequently has to do with cover. Birds need to feel safe in order to approach a feeder. While it may not always be apparent to us, certain placements may represent a high-risk venture for birds. For example, there may be a particular spot where a feral cat spends hour upon hour awaiting a hungry bird. Or the danger may come rrom above: more and more reports are coming in of Coopers' and Sharp-shinned Hawks staking out local feeders as prime hunting locations. (When this comes over the phone to me, there is sometimes a bit of grief counseling to be done, but I must admit to a certain amount of inner glee: the ecosystem is working! The top predators are back!)

Experts recommend a placement of feeders at about 10 feet from the closest cover. This provides birds a nearby haven when startled and a "way-station" to use when approaching the feeder, from which they can scan for trouble. But it's also far enough away that cats and other ground predators lose the advantage of the sudden lunge.

Other considerations when placing a feeder are visibility (you do want to see the birds, don't you?), and convenience for refilling. If you make the location too hard to reach, it will be hard to stick with the routine over the long haul.

Several serious avian diseases can be spread through birds' use of feeders. Some, like Salmonella, can be transmitted to humans, so special care should be taken to keep yourself healthy as you clean the feeders. Instructions for cleaning are provided in the next section on winter feeding.

Winter Bird-feeding Counts Most

Winter is the season when supplemental feeding may contribute the most to songbird health and survival. During this season, the abundance of berries, fruits, and especially insects, (which represent the bulk of most songbirds' diets during the warmer months), has dwindled to the point where resident species must shift their diets to seeds and fruits to survive.

In our immediate area, it's unlikely that wild birds will undergo the large-scale population crashes that often follow, say, a three-day ice storm in the Midwest. But individual birds may indeed live or die depending on whether we stay alert to their changing needs during foul weather episodes. In general, the smaller the bird, the greater the challenge it faces in coping with winter's long nights, cold temperatures, and diminished food supply. But any bird will benefit from a dependable source of daily nutrition and from some built-up fat reserves that provide it with an internal, emergency energy source - and perhaps some direct insulation as well.

Some Winter Do's and Don'ts

Bird-feeders would do well to adopt the first principle of Emergency First Aid, namely, "Do no harm." Improperly maintained, or erratically filled feeders can do more harm than good to the birds we love. Here are a few pointers for ensuring that the balance tips strongly to the positive side at your feeders.

  1. DO clean your feeders thoroughly at the beginning of the rainy season, and as often as you can stand to throughout the year (once a month would be a fine target; twice a year would be a lot better than nothing. Use soap or detergent, then dip for several minutes in a solution of 1 part chlorine bleach to 10 parts water. Rinse and dry thoroughly before refilling.) Cleaning is especially important during wet weather, because some of the most serious of the diseases that may be spread at feeders are mold-borne (and molds, of course, thrive on moisture.) If your feeder collects a residue of uneaten seed at the bottom that tends to stay there for long periods, as do many "tube" feeders, remove it periodically. Not only might it harbor pathogenic microbes, but it's probably pretty yucky.
  2. DO check your feeders during or immediately after a heavy rain to make sure the seed is staying dry. If not, move it. This is another way to prevent mold growth and disease transmission.
  3. DON'T take down your hummingbird feeders. This is one of the most important differences between our area and the rest of the country with regard to bird-feeding priorities. Many national birding publications advise taking these down over the winter, but locally, that's the last thing you'd want to do! Our climate is mild enough to permit the Anna's Hummingbird to overwinter, but harsh weather still takes it's toll, and many don't make it. Removal of a steady food source may doom birds that have set up a territory around it.
  4. DON'T worry about confusing migratory birds and causing them to linger beyond their safe traveling period by maintaining feeders during fall and winter. The scientific evidence is now very clear that day length, or photoperiod, is the controlling factor for the timing of migration, not food availability.
  5. DO put up a suet feeder. Suet, a rendered form of animal fat, has the highest energy content of any bird food and is very popular during cold weather. It will often bring in a variety of species, such as woodpeckers, that would rarely, if ever, be seen at other feeder types.
  6. DO consider putting out black oil sunflower seed, even if you avoid it at other times. Although it's not likely to be a matter of survival in our area, the higher oil content provides birds with more energy than other seed types.
  7. DO consider joining the Cornell Lab of Ornithology's FeederWatch program. You can add valuable information to an emerging scientific portrait of the wintering birds of North America. All you have to do is catalog each species visiting your feeders one day a week for a 10-week period through the winter, even if you can only watch it for a short while on any given survey day. There is a small subscription fee, and you must use their special data-collection forms. The program starts in mid-November, so if you're interested, act quickly! Call CLO's FeederWatch program office at (800) 843-BIRD. I will be happy to serve as your local contact and troubleshooter for the program from the SCVAS office.