Editor’s note: Rick Hollis of rural North Liberty, is past president and newsletter editor for the Iowa City Bird Club.
By Rick Hollis, community contributor
Winter bird-watching can be very exciting.
Last year we saw a snowy owl irruption (yes that is spelled right). An irruption is the unusual occurrence of higher than normal numbers of species, usually due to the failure of a food source in their normal wintering areas.
Most winters there are a number of species that show up at our feeders that we do not see in summer, like dark-eyed juncos (my Mom called them snowbirds) with their white bellies and dark coats and at rural feeders and American tree sparrows. Purple finches also can be spotted, although they were seen more often before the arrival of house finches.
This year there has been a mild irruption of the group of birds that we collectively call winter finches, even if some are not finches.
Red-breasted nuthatch is our normal white-breasted nuthatch’s cousin. They look much like the white-breasted, but are smaller and tamer. The males have a bright cinnamon belly and chest, not just the red under the tail. The females are more of a tan color. We see them every couple of years and this year many people are seeing them. This is the “winter finch” that is not a finch. Red-breasted nuthatches come to Iowa every two or three years, although a few are always seen.
Some people are lucky enough to see purple finches every year. At my feeders, they are rather uncommon visitors.
Next are the two species of crossbill. They look like they have deformed bills. The reason their bills are so unusual is that they eat pine seeds, which requires prying the cone’s scales apart. Since the muscles that close a bird’s bills are stronger than the opener muscles, crossbills have evolved crossed bill tips. They insert them between scales with their beak partly open, close their bills to pry the scales apart and dine. The most likely feeders to host crossbills are ones near mature conifers.
Red crossbill is one of the two species seen in our state this year. They are unusual in that there are there are multiple different kinds of red crossbills, called types. Types differ in their call notes, bill size, diet and distribution.
This year it is likely we are seeing Type 3 (small-billed), from the Pacific Northwest and perhaps Type 2 (large-billed) red crossbills. Red crossbill males are reddish with darker wings. Females are grey-tan.
The white-winged crossbill has two white splashes on their dark wings. The males are pinkish and females are yellow-tan. White-winged Crossbills show up in higher numbers in Iowa every six or seven years
Common redpoll are closely related to American goldfinches, which they closely resemble. They lack yellow and have small dark masks and red foreheads. Males have pink bellies.
Pine siskin are a bit smaller than American goldfinches and heavily streaked. They have tiny, pointy bills. I often notice them by their calls, which are a raspy, ascending zrrrrt. Both siskins and redpolls have forked tails like goldfinches, which is one way to separate them from house or purple finches. Pine siskin numbers peak every couple of years. There are reports of sick pine siskins around. Pine siskins are especially susceptible to salmonella, so feeder cleanliness is important.
The evening grosbeak are the rarest of the bunch so far. This species used to show up every 10 to 12 years, but since the 1980s has practically disappeared. They are larger than cardinals and have really massive, grey-green bills. Males have quite a bit of yellow in their plumage whereas females are gray. Both sexes have a good amount of white on their wings.
Pine grosbeak is another irruptive species, which is rarely seen in Iowa.
As I finished writing this, a single common redpoll and several pine siskins are being seen at the feeders at the CEC in Kent Park.
For pictures on any of these species, go to www.allaboutbirds.org/guide/search