Squirrels and Mast Years

Over a period of about ten days in September, I visited the Cambridge University Botanic Garden three times. On the first two visits I saw maybe five or six squirrels but on the third visit I saw around fifty young squirrels. Why so many squirrels, so suddenly?

I asked CUGB, and the wildlife experts wrote that in their opinion the reason was that:

Last year was a mast year for oaks. Mast years happen in intervals of round 7-10 years and are years when oaks produce masses of acorns and this is synchronised- so all the oaks in an area will do the same thing. This provides an abundance of food for species like squirrels who then overwinter very well and then are able to breed really well the following year. Now’s the time that lots of young ones are becoming independent and are out and about more. Hence lots of squirrels. When its not a mast year, there are fewer acorns and this is a way that plants can keep their herbivores in check. See this article in the Woodland Trust site, what is a mast year?

Hop Hornbeam

Where are the seed cases from the Hop hornbeam? When I went to look at the tree last week, I could only find two, hanging on the outer branches over the path. The tree has seed cases about two inches long made up of multiple little squashy (air filled?) sacs. I searched for several minutes and couldn’t find any on the grass below the tree. There were plenty of wind-blown leaves, so what happened to the seed cases? I don’t think they crumbled to nothing because I have one on the table that I collected months ago, and it is holding together with no signs of disintegrating.

Had squirrels taken them? That might be. It would fit with the relative inaccessibility of the two cases hanging on the furthest thin branches. Then again, was that location really squirrel-proof? Perhaps another smaller rodent, but what would be big enough to pulverise the seed case in search of the seeds?

The tree is on the path leading to the cafe, just to the left of the path when one is coming from the Hills Road entrance,

Red Admirals

A few days ago in the Botanic Garden, at the Copper Beech near the Hills Road entrance, I saw two Red Admiral butterflies flying about faster than I ever thought butterflies could fly. The jinked and flew like little maniacs. It was not until one landed on the gravel path that I could tell what they were.

It happened that I had stopped and turned around to look at the Copper Beech because on the way in I noticed it had lost its copper colour. It is still warm in mid November, and the leaves on the tree still had life in them, they had just lost their copper colour.

The beech is in shade on the north side and in full sun on the south side and I have noticed before that the red and purple of the leaves only happens on the side that catches the sun. Now, in the middle of November, all the leaves were more or less the same colour – greenish yellow.