Northern flickers and European starlings

There have been three flickers in the yard everyday now for about a week or so, one female and two males. They seem to be fighting for her attention, and for the cold ants in our anthill . By Saturday morning it looked like one had the upper hand in the battle for her affection and the nest box (see the handsome gentleman above). The disconcerting, yet predictable part about flickers is there relationship with European starlings. Saturday morning also marked the first day of the year where I saw a European starling in my yard. This is not good, but I knew it would happen as soon as excavation started on the nest box.

Few are aware of the relationship between European starlings and flickers. A really unfortunate trend in the expansion of European starlings is the colonization and parasitism of flicker nesting cavities. Northern flickers are an incredibly vital component to forested ecosystems across the country. They are abundant primary excavators and so many species (secondary excavators) rely on them to hollow out nest sites in standing snags. The large cavities they create are used by other birds (including screech-owls, and American kestrels), and animals, after lfickers abandon them in the summer. Northern flickers are ground feeding woodpeckers that mainly eat ants. Because of their abundance, northern flickers can control populations of ants including wood-boring species.

As secondary excavators, European starlings, rerly on flickers to excavte a cavity and an entrance hole of roughly the same size as a northern flicker. The starlings let the flickers do the work of finding a suitable site, excavating a cavity and then the starlings move in to over take the flickers and seize the nesting cavity.

Northern flicker status: population declines
Recently there has been a lot of concern over status and population trends of northern flickers. Although they are still abundant, they have declined over the past 20 years. This decline is from a combination of factors, including habitat loss, nesting site loss, competition with European starlings, and even from lawn insecticides. These declines, coupled with the loss of habitat and ever-encroaching invasive species can have serious, deleterious effects on many bird species and other wildlife.

What you can do
Providing a nest box is a start, since snags are often removed, reducing the availability of nest sites for flickers and other cavity nesting species. But just providing a nesting place is not enough. It is a huge responsibility of nest box stewards to protect the nest box from invasion by European starlings.

If European starlings begin to use your nest box, do not just add more nest boxes to attract flickers - this will only get you more starlings. Do what you can to dissuade starlings from nesting, and this usually means lethal control, similar to squirrel management. However, begin first by plugging up any entrance holes where they may be nesting, remove their nesting material. Or remove their eggs.

Unlike woodpeckers, European starlings bring in nesting material to their cavities. This is likely an adaptation that most secondary cavity nesters employ. Since they do not excavate a clean, parasite-free area for their nestlings, they will line their nests with green, fragrant herbs as an insecticide.

Some think that northern flickers are adapting to European starlings nesting later, after European starlings have fledged. This is more than likely a nice little wish. With climate change and other factors, if nothing else, northern flicker (and other species) nesting dates might be getting earlier, rather than later. Nest timing is critical and centers on resource availability. If northern flickers are indeed nesting later, it is probably to their detriment.

European starlings in North America
European starlings have a very interesting and storied history in our country. The first two attempts to introduce the European starlings into North America failed; unfortunately the third attempt did not. There are now an estimated 200 million European starlings in North America, one-third of all the European starlings in the world. All the European starlings in North America descended from 100 that were released in New York’s Central Park by Eugene Schieffelin in 1890 (60 birds) and 1891 (40 birds).

Although many believe Schieffelin was trying to introduce every bird species mentioned in the works of Shakespeare to North America, there is little evidence to support this. It is more likely he was merely trying to control pests, and probably the same pests that he tried to get rid of when he introduced the house sparrow 30 years prior. Although the house sparrow, and European starling introductions were quite successful, fortunately his attempts to introduce bullfinches, chaffinches, nightingales, and skylarks were not. Busy guy.

Although ecologically devastating, biologically it is actually really interesting that European starlings survived and flourished, despite being descended from such a small source. Evidently, this genetic bottleneck has not adversely affected the persistence of European starlings in this country.

European starlings are generalists in the food they eat and habitats they use. Furthermore, European starlings tolerate human-modified landscapes, and proximity to humans- habitats that many native species are driven from. European starlings are aggressive and gregarious and easily compete with native birds for resources. They form huge flocks (up to a few thousand birds), to feed and roost, and they have a high tolerance to nesting in close proximity to one another.

European starlings tolerate suburbs and urban areas and flourish with conventions like lawns. They do really well foraging in lawns, much better than native birds like American robins that people commonly see feeding in lawns (one of the few native birds to do so). One of the main reasons European starlings do so well in lawns, is that they excel at excavating worms and insects out of the tightly woven turf grass. Their jaws have remarkable strength for opening (as oppesed to closing), and this makes them adept at opening a hole large enough in turf to remove worms and insects. By providing a lawn, this is one of the few species that will benefit.

Because they are so abundant, and good insectivores, there is the misconception that European starlings are great “biological control” agents and can be used to control insect pests in agricultural settings. But because they are such generalist feeders, they will not just eat "pests" but also important agricultural crops like grapes, olives, and tomatoes. In Australia, where they were introduced for pest control, European starlings now threaten the country's economy and biodiversity.