Photo by Julie Covey
Invasive species often have advantages over our local plant and animal species. These invaders are frequently more aggressive and have other abilities to out-compete North American natives. One advantage well demonstrated in nonnative plants is the ability to bloom early in the spring thereby getting a fast start on the growing season. Invaders such as common buckthorn and some honeysuckles often display their foliage long before native trees and shrubs. Similar ability to get a jump start is evident in European Starling, House Sparrow, Rock Pigeon and Mute Swan – all non-native birds.
Usually by late January, Starling beaks are already turning a bright yellow color in preparation for the breeding season. Even within the large flocks that winter with us, the careful observer can discern behaviors that indicate breeding pairs are forming. These couples begin breaking off from the
flocks and go searching for nest sites. Combined with the aggressive nature of this species, the early occupancy and defense of nest cavities gives them a tremendous edge over competitors. Rare is the Eastern Bluebird or Red-headed Woodpecker that can protect a nest cavity against these avian
bullies. Even the woodpeckers’ newly constructed nest sites may be seized and the builder must wait for these usurpers to finish and vacate the premises.
Early pairing and breeding occurs in European Starling and House Sparrow to the degree that it excludes many native birds from nesting near human habitation. The only way to solve that problem is for us to intervene using lethal methods to deal with these feathered aliens. Understandably many homeowners are reluctant to resort to such tactics and in any case lots of time, persistence, and determination on our part is required. Also around large farms the masses of these two species present generally renders the most determined human efforts useless.
Most of our invasive birds were introduced by humans with the best of intentions. Unfortunately, with very few exceptions, these efforts have created ecological disasters. Declines of many native cavity nesting bird species can be directly traced to the impacts of large European Starling and House Sparrow populations. Ironically the Starling is declining over much of its native range in the Old World. The reasons for this vary depending upon region but in some areas the population loss is significant. Although not practical, the idea of a repatriation program to the old countries of their ancestors is a thought that warms this birder’s heart.