Tag Archives: biology

Autumn Geese and a natural mystery

Autumn came in very slowly this year, but it turned quite cold quite quickly. However, now at last we are getting rain in proper autumn levels. We had proportionally very little rain all last winter, spring and summer. Finally the geese have started to arrive too. Here are two of the most common species, the Brent Goose (Branta bernicla):

and a flock of Greylag (Anser anser), with two Rooks (Corvus frugilegus) providing a sense of scale:

All of these birds are pictured at the famous Kilcoole Breaches and nature reserve.

There have been two noticeable trends this autumn – firstly there have been far less spiders than you would expect on average, particularly House Spiders. But all species seem to be lower in number than usual. The only spider species at normal levels, or apparently normal levels, has been the Garden Spider (Araneus diadematus), which is also the most obvious autumn spider:

    Conversely, there has been a population explosion of Brown Rats (Rattus norvegicus) which has been attributed to the long hot summer and the summer heatwave of May, June and July which almost led to a severe drought. The increased population of Brown Rats very likely has reduced the number of spiders, as rats and mice will happily eat large spiders. More rats equals less spiders.

However, from my own observations I disagree that the summer heatwave is responsible for the population explosion of rats – back in March, during the heavy snows, there was a massive surge in rat numbers. They were especially attracted to bird feeders. The winter had been very cold even before the snows arrived late, and it seems that this factor drew rats from the countryside towards human settlements in order to find food and warmth. But whatever the exact cause, there were a lot of them around, although numbers at last seem to be returning to normal:

Gently Fading Summer

This year we had an extraordinary summer. Until August we had little or no rain, and some very consistently warm temperatures. August brought some badly-needed rain and this gradually put an end to a dangerous situation, gorse fires having become a serious threat to the landscape. It was a great year for butterflies, and here are some examples:

Peacock (Inachis io)

Small Tortoiseshells (Aglais urticae) gathered on a Butterfly Bush (Buddleia davidii)

Silver-washed Fritillary (Argynnis paphia)

Meadow Brown (Maniola jurtina)

Meadow Brown captured by Flower Crab Spider (Misumena vatia)

But butterflies were not the only brightly-coloured winged insects flying about in the day. Here is a beautiful Six-spot Burnet moth (Zygaena filipendulae), a species which has toxins in its body which birds find distasteful.

Six-spot Burnet moth feeding on Ragwort.

Of course, most moths are nocturnal, such as these beauties which were attracted to the light of a window:

Lesser Broad-bordered Yellow Underwing moth (Noctua janthe)

Brimstone Moth (Opisthograptis luteolata)

Moths, in particular depend on wildflowers, and in August, and even now in September some wildflowers are blooming brightly, such as the hedge-climbing Honeysuckle (

Honeysuckle or Woodbine (Lonicera periclymenum)

On 7th August I saw my last Swift. Swifts arrive in May, usually about a month after the Swallows, House Martins and Sand Martins. Last in and first out, they seem to follow their migration patterns almost like clockwork, and leave very early in August. Most are recorded as leaving the British Isles (a geographical term which includes Ireland, as the second-largest island in the archipelago). Now, however, the Swallows are preparing to leave, and the young are perching on wires, resting, before migrating to southern Africa.

Barn Swallows (Hirundo rustica) gathering on wires before migration. The adults are cajoling the youngsters into taking flight. 

True Spring… at last

Scarcely a week has passed since we had our unexpected snow storm, but at last true spring has begun, and here is a little video I made of the transition, and the exciting arrival of a Treecreeper (Certhia familiaris), a small bird which creeps up walls and tree trunks feeding on insects and spiders as it goes. And then a very exciting scene which proves spring is, at last, definitely here:

However, not only have birds been collecting nesting materials, but finally frogspawn appeared in my garden pond, and lots of it:

This is the spawn of the Common Frog, Rana temporaria.  For those of you who are wondering what the green on the pond is, it is actually tiny leaves of Duckweed, a plant which exists only as a leaf, and which reproduces by cell division – one leaf turns into two, two into four, four into eight, eight into sixteen. And that is how it forms carpets of green on ponds.