Invasive animal species no.3 – ring-necked parakeets

(I’ll apologise in advance for the pictures, these are quite tricky creatures to photograph!)

The ring-necked parakeet is the only parrot to be found living successfully in the UK. The species originates from South Asia but has been a popular pet in Europe for many years – this has led to many birds escaping or simply being set free here.


City parks provide the ideal habitat: since the 1970s population sizes have been on the increase and the parakeets are now found across most of England. When I first arrived in Manchester and began to explore nearby parks I was quite surprised to see ring-necked parakeets as I had assumed that they would not cope with the colder weather in the north of the country.


Unlike the other two species that I have covered in this series (grey squirrels and Canadian geese), the ring-necked parakeet has not had any major effects on the ecology of the habitats it has moved into. However it has been here for a relatively short amount of time compared with other invasive species and with numbers on the rise it is likely that this introduction could prove to be detrimental to British wildlife.


Certain people are eligible for a license which enables them to kill ring-necked parakeets or to destroy eggs and nests. Once again this raises the question of whether this is ethical or not – we are the reason that this species ended up here in the first place and at this present time it is not causing any real disruption in UK ecosystems.


However, this could be considered a preventative measure to avoid damage to British wildlife: past experience shows us that the sudden introduction of a species is rarely beneficial. It is inevitable that the parakeets will begin to compete with native species for resources and even the decline of just one bird could send the whole food chain into chaos.

If ring-necked parakeets are going to be allowed to stay in the UK, their populations and impact should be carefully monitored to ensure that the lives of native species are not compromised.


Sources used in this blog post:



Invasive animal species no.2 – Canada Geese

Canada geese were initially introduced to the UK as an ornamental species in the 17th century and since then they have flourished: the past forty years in particular have seen a significant increase in the population size.

They are attractive birds and the majority of people probably wouldn’t think twice about whether they are supposed to be in our parks and lakes – I wasn’t even aware that they were a foreign species until I began reading up on the topic a few weeks ago. Whilst much less emphasis is placed on them than other invasive species (grey squirrels, for example – see my previous blog post for more information), they do still have detrimental effects in British ecosystems.


Canada geese can cause damage to plant life – by eating aquatic plants they can disrupt oxygen levels in lakes, which has an impact on organisms in the water. On the sides of lakes, terrestrial plants such as grass are trampled and eaten. 

Their droppings can appear unsightly and contain substances which in large quantities could affect aquatic life – these include nitrate and phosphate. Continual entries and exits from the lakes can also cause erosion of the banks.


Certain people are eligible for a license which grants them permission to kill Canada geese and to destroy their nests and eggs. 

Some other less extreme methods can be used to manage populations: many are fed by humans, so discouraging this activity is an option and strategic fencing can prevent geese from settling in an area in the first place. 


Whilst this may be considered as necessary action to protect British lakes and parks, perhaps we should also recognise that Canada geese are not the only waterfowl to inhabit these areas and so are not the only species contributing to the problem. That said, they are on the rise and could begin to dominate over other native species that exploit the same niche. 

The idea of having to remove Canada geese due to us wrongly introducing them in the first place is a controversial one, but we have to understand that as an invasive species they could have a long term negative impact on British ecosystems.


Sources used in this blog post: 

The RSPB: 

English Heritage: 

Invasive animal species no.1 – the grey squirrel

The grey squirrel is a small rodent frequently seen across most of England and Wales – its lively character makes it quite an entertaining creature to watch and it seems to blend in perfectly in our woodlands or city parks. However, this is a species which is not native to Britain and since its introduction in the 19th century it has wreaked havoc on our ecosystems.


Originating from North America, they were first imported to be released onto estates but soon spread beyond and began to impede on the lives of the native species already existing there.

Perhaps the most famous example of these is the red squirrel, whose population has declined dramatically due to being out-competed by the greys for food and by being infected with squirrel pox virus. Grey squirrels are carriers of this disease but unfortunately it proved to be fatal for the reds.


Grey squirrels also strip the bark off trees such as beech and oak, and on occasion are known to take birds’ eggs from their nests.

So, should grey squirrels be culled? There is a law that allows the UK to poison, trap and kill the rodents, but is it the right thing to do?


Whilst it would aid the red squirrel population, it could be argued that the greys have been here for a decent length of time now and to remove them could cause more disruption to the ecosystems that they have become a part of.


It may also be worth considering that it is only through the actions of humans that these squirrels arrived here in the first place – would it be fair to kill them because of our own mistakes?


In my opinion the situation should be carefully assessed before any drastic action is taken. Numerous culls of other animal species have been ineffective so if this was decided as the course of action then it should be carried out in a controlled area beforehand so that the effects could be monitored.

As sad as it would be to see the death of hundreds of squirrels, it could be for a greater good.


Sources used in this blog post:


The Guardian –

The Telegraph –