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Introduction
Introduction
Grey squirrels are acknowledged as invasive alien species, that are threatening the native European red squirrels in the British Isles and part of northern Italy. The spread of the grey squirrel represents a big problem. We need to avoid the extinction of red squirrels, that, unfortunately is progressing.
Monza Park is one of the few urban parks in Lombardy that still hosts the red squirrel, which is the only native arboreal squirrel species in Italy and Europe. Red squirrels first appeared in the park around 2000, likely arriving from Montevecchia where they had been reintroduced, and the species quickly spread to reach Monza Park. However, in the last few years the number of red squirrels started decreasing rapidly due to the spread of grey squirrels.
The Lombardy Region launched the "Rossoscoiattolo" project, a European LIFE initiative, to raise awareness about protecting the species, and installed an observation structure in the park near the Vedano entrance Il Cittadino di Monza e BrianzaRossoscoiattolo. The observatory includes feeders, jumping platforms, and nest boxes equipped with webcams powered by solar panels, along with educational signage about conservation issues related to competition with the grey squirrel. However the project ended a few years ago and nowadays no actions are being taken to protect red squirrels.
What is a red squirrel?
What is a red squirrel?
Red squirrels (sciurus vulgaris) are small mammmals with bushy tail that live in forests across Euorope and Asia. An adult squirrel weighs about 240-400 grams and has a beautiful thick tail. These squirrel are active during the day and don’t hibernate in winter like some other animals.
Red squirrels build nests in the tree branches where mother squirrels raise their babies. Mother squirrels takes care of their babies for 8-10 weeks. During the day, squirrels rest in their nest or iniside hollow trees.
Main characteristics of red squirrels:
Only native species in Italy.
Medium size squirrel (270-360g adults) that lives on trees.
Their fur can be very variable for clour and shade (red, grey, sometimes black).
No white stripe on the external part of the tail.
Usually, it’s got ear tufts.
The problem: grey squirrels
The problem: grey squirrels
Red squirrels in Italy are facing a serious threat from an invasive species called grey squirrel, originally from North America. They are nowadays found in several Italian regions including piedmont, lombardy, veneto, liguria and umbria.
Grey squirrels are bigger and stronger competitors than red squirrels: when grey squirrels move into an area, bad things happen to red squirrels!
Case study
Case study
Eradication of grey squirrels from Aberdeen
Eradication of grey squirrels from Aberdeen
In north-east Scotland, the SSRS (Saving Scotland's Red Squirrels) team focused on removing grey squirrels from the city of Aberdeen. When unchecked, in fact, they continued to threaten red squirrels.
All red squirrel habitats in Aberdeen are at risk, due to the possible return of grey squirrels, until grey squirrels have been eliminated from Aberdeen until the very end.If there is no grey squirrel, the red squirrel tends to re-inhabit cities as well.
In 2021 371 grey squirrels were trapperd (compared to 153 in 2022, 95 in 2023 and 6 in 2024).
In 2024, approximately 8,000 feedbox checks were carried out, resulting in the detection of one gray squirrel and 4,219 red squirrels.
Staff collect samples and use microscopes to identify each sample at the species level as soon as it arrives. When a gray squirrel is detected, staff immediately respond with traps. Any detection of grey squirrels is addressed as soon as possible, using traps in conjunction with a police trap alarm.
Gasmere to Grizedale project
Gasmere to Grizedale project
Project Aim:
Project Aim:
To control grey squirrels: targeting eradication in priority areas.
Monitor and protect red squirrels in the lakeland heartland and create a red squirrel ranger.
Explore the potential of a captive breeding programme to encourage the release of red squirrels with key genetic bloodlines
Success indicators of this projects:
Success indicators of this projects:
+1000 grey squirrels removed in 19 months
Lessons learned:
Lessons learned:
Traps must be sanitised daily to prevent disease spread.
Efforts to control the grey squirrel must be targeted and not spread too thinly.
Red squirrels must not be provided with supplemental feeding unless extensive grey squirrel control has been implemented. Otherwise special feeders for red squirrels are essential.
Removing gray squirrel carcasses after control operations is important to reduce predation on surviving red squirrels. Leaving carcasses out encourages predator activity.
It is important to stick to careful plans and expect grey squirrels to "recover" within a few months of being checked.
Non-invasive monitoring techniques are an absolute must, thermal imagers and thermal drones being employed alongside volunteers to get an 'eyes on' approach to red sightings is an adaptive approach.
Grasmere to Grizedale project grey squirrel control area. Red squirrel records are shown by red circles.
Red squirrel cull record in the project areas.
How can we help red squirrels?
How can we help red squirrels?
Scientists have developed two main ways to help red squirrel population: direct and indirect support.
What is direct support?
What is direct support?
Sometimes scientists move red squirrels to new areas where they can live safely. This is called restocking or reintroduction. Restocking means releasing squirrels in areas where few red squirrels already live; reintroduction means releasing them in an area where they have completely disappeared. In both cases, before moving any red quirrels, all grey squirrels in that area must be removed otherwise thwy will face the same problem.
Requirements for a good release area
Requirements for a good release area
Size: at least 100 hectars (about 200 soccer fields)
Trees: must have trees that produce food (walnuts, hazelnuts etc.)
Shelter: at least 10 large trees per hectar with cavities for nesting
Safety: no feral cat olonies nearby (cats could hunt squirrels)
Success stories
Success stories
In belgium 8 red squirrels were released in a park and their popularion grew four times larger in just 2.5 years
In Ireland many relased squirrels survived and successfully had babies.
Scientists estimate you need at least 35 squirrels to start a healthy population that can survive for 100 years.
What is indirect support?
What is indirect support?
Indirect support means making the environment better for red squirrels without actually moving them.
- Nest boxes
Nest boxes are little wodden houses for squirrels! They:
provide safe places for mother to raise babies
offer shelter during bad weather
should be made from wood treated with non-toxic materials
must be placed at least 3.5 meters high on tree trunks
should have an entrence hole of 6.3 cm ( perfect size for red squirrels).
In england, studies showed squirrels used nest boxes most in summer and less in spring.
2. Feeders
2. Feeders
Feeders provide extra food for squirrels and should contain:
walnuts
hazelnuts
apples
Warning: feeders should only be used where there are NO grey squirrels, beacause grey squirrels can also use them!
3. Planting trees
3. Planting trees
Planting the right trees helps red squirrels find food naturally. The best trees to plant are:
walnut trees
hazel trees
linden trees
cherry trees
elm trees
4. Creating connettions between forests area
4. Creating connettions between forests area
Red squirrels need to move between differnet forest areas to find mates and food. Scientist create "ecological corridors" by:
planting rows of trees between trees
protecting vegetation along streams and ditches
creating ‘stepping stones’ of small wooden areas
This helps squirrels population stay healthy and connected instead of being isolated.
Why is this important?
Why is this important?
Red squirrels are an important part of italy’s natural heritage and biodiversity.
While they are not currently considered endangered worldwild, their populations are decreasing in many areas, espacially where grey squirrels have been introduced.
Every animal plays an important role in nature’s balance, and protecting red squirrels means protecting the forests and ecosystem they live in!
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