Original Author: Stewart Smith – Squirrel Volunteer
A good mast year with lots of nuts around is good news and bad news for red squirrels. Lots of food means an easier winter but it also means grey squirrels have an easy time too and will have higher breeding success the following year.
As our statutory 3 days of summer in Scotland has elapsed, we have well and truly landed into a decidedly mixed autumn, which is looking likely to be replaced by another mild winter. This is certainly positive news, in the short term at least, for our squirrel populations, especially when coupled with an exceptional mast year. A mast year is when, for reasons still not fully understood by academics and naturalists, there is an unusual abundance of seed, fruits and nuts on our trees. So much so that it would be impossible for creatures to consume the entire crop. This autumn with trees bowing under the weight of their own produce, red squirrels will be benefiting. Is there plenty of food on the trees in your area?
As with humans in the supermarket “reduced” aisle, red squirrels will take full advantage of the opportunity and load up their plates at the forest buffet. This results in a boost in body weight which helps them to withstand harsh winters and will mean that more females are likely to bear two litters next year. Red squirrels have the ability to cache food for lean periods which means that even if there is a cold snap towards spring, the supplies put by this autumn will be enough to cover shortfalls during the breeding season.
Conversely, of course, a mast year is ominously good news for the health and reproduction of greys, and will be a boost to their populations too. The results of our 2017 spring survey will be analysed with particular interest to assess the scale of the impact of a mild and plentiful year on numbers of greys.
It is years like this that the excellent work of our volunteers in their endeavours to trap grey squirrels is even more pertinent in limiting the spread and increase in grey populations.