Friday, February 07, 2014

Pity the Poor Immigrant

I read the other day that New York State is going to join the list of US states trying to wipe out their populations of Mute Swans. 

Animal rights activists and many members of the public are understandably up in arms about the decision to kill off these beautiful birds. However, birding and conservation organizations are generally in favor of the decision. This is because Mute Swans, originally imported from Europe in the 1800s, are an invasive species and their spread is threatening the future of some native bird species.

Mute Swans are not an issue here in southeast Texas but three other invasive bird species are causing problems here, as they are all over the USA.

Rock Dove (Feral Pigeon)

We tend to associate Rock Doves with urban areas but they are also common in many suburban and rural areas. Originally imported from Europe, they are now a significant agricultural pest and they also carry a range of diseases that can be passed to humans.

European Starling

Introduced into New York in 1890, European Starlings have now spread across the country and they probably total somewhere around 200 million birds. Like Rock Doves, Starlings are an agricultural pest and carry a range of diseases. 

House Sparrow

The third common invasive species is the House Sparrow, sometimes referred to as the English Sparrow. This species was brought to New York from England in the late 1800s and has thrived in its new homeland. 

Male House Sparrow

Female House Sparrow

While many Americans find House Sparrows attractive and welcome them to their yards, birders generally detest them because they are displacing some native species. Some birders even trap and kill them.

Personally, I am torn when it comes to House Sparrows. Although I curse at them when dozens descend on our feeders, I don't think I could ever bring myself to kill them. Like me, they are immigrants from England; and unlike me, they didn't choose to come here. 

Another Non-native Bird

Of course, not all non-native birds in the USA are considered to be invasive. A good example of a non-native species that is not generally regarded as being invasive is the Cattle Egret. Unlike Rock Doves and European Starlings, these birds do not eat farmers' crops and do not pose a health risk to humans.

Probably another reason why Cattle Egrets are not usually regarded as invasive is that they were not deliberately introduced into the USA. Instead they made their own way here from Africa by way of Latin America. Now a common sight all over the USA, they often hang out with cows, feeding on the bugs and small animals which the cows disturb as they graze.


Dorothy Borders said...

Excellent post. Non-native species always present a quandary and a moral dilemma for animal lovers. The decision to kill animals that did not choose to come here is always a difficult one, but in the case of the Mute Swan which is so destructive to the habitat and to native species it is probably justified.

Jeff said...

I agree. It is very difficult to kill any animal but, for birders, especially a bird.