little egret

[islandgun]

On 25/04/2020 at 10:56, chrisjpainter said:

Invasive simply means a species that got here by non-natural (human) means, whether deliberately or accidentally. 

Your classic invasives - grey squirrels, mink and zebra mussels - were brought here by humans and cause a lot of damage to native wildlife, so it's easy to see them as 'invasive'. They benefit to the detriment of local wildlife even though they shouldn't be there.

It's a bit complicated when there's no specific evidence that they're causing ecological damage. They may have found an ecological niche that was hitherto unfilled and doesn't impact other species detrimentally, like the little owl. Technically it's an invasive species but does it really matter?

Then you get things like the Glossy Ibis, arriving here through a process of natural colonisation. They will never be classed as invasive, because humans didn't bring them here, but they might be put on the pest species list if it's clear that they're causing detrimental damage and that controlling them won't result in extinction. 

We like to talk in terms of 'natural range' but for an island nation this only really makes sense for mammalian species, as they can't get here except via non-natural means. a natural range simply means is it natural for the species to be here? UK wetlands tick all the boxes for Glossy Ibis now and they're getting here through natural behaviour. The idea of historical range makes more sense, but if you're looking to pause the ecological clock at historical ranges, at what point in history do you do it? Whenever you pick, you're gonna have to kill a lot of stuff or introduce a lot of stuff to do it!

We have a little Egret that visits here in October and has done for the last 3 years. bear in mind we are approx 50 miles west of Skye.. My thinking is that its the first of a possible migration North and West. it will be very interesting to see if it ever turns up at a different time or perhaps with a mate