Friday, 20 December 2013

A territorial robin

We seem to have a very territorial robin in the garden, and he, or she, has laid claim to the area around the feeders at the bottom of the garden. Whenever any smaller bid approaches the feeders it is chased away. However, there does seem to be a hierarchy, and the robin only chases away blue tits, great tits or coal tits.

This morning it sat and watched as a nuthatche was feeding. When the male house sparrow visited for breakfast, the robin again sat and watched, but it was very wary, keeping a close eye on the sparrow. The robin can just be seen watching in the photo below.

Saturday, 14 December 2013

Missing legs

Last Saturday I was sent outside with yards of lights, wires and plugs with the instruction to light up the front of the house and the shrubs in the garden. Luckily it wasn't too cold and I didn't loose any finger to frost bite this year for a change! As I was fighting manfully with the topiary bush by the front door I found a late season Dicranopalpus ramosus on the wall.

It had a few legs missing, well in fact most of the legs are no longer there. This lack of limbs does not seem to have affected its survival this late into the season though. Like spiders there should be 4 pairs, but this is where the similarity between harvestmen and spiders stop. In harvestmen the second pair of legs are longer than the others and act as sensory limbs.

Harvestman belong to the order Opiliones, one of 11 orders placed in the class Arachnida. True spiders belong to the order Araneae. Harvestman differ from spiders by having only one pair of eyes on a centrally positioned ocularium, they do not have venom glands or hollow fangs with which to kill live prey and being devoid of silk glands do not spin webs. The cephalothorax and opisthosoma joined by a broad connection giving the whole body the appearance of being as one piece and the second pair of legs are longer than the other three pairs. 

Harvestmen will eat all kinds of food. Their omnivorous habits mean they will eat dead squashed slugs, bird droppings, jam, fruit and other plant remains, as well as live small invertebrates that they might catch. Generally they are nocturnal and can be found hiding under ivy, amongst grass stems, and other vegetation, under stones, bark and logs and inside cool damp buildings like sheds and outside toilets. Their common name derives from the fact that most are mature in autumn, at the time of harvesting.

The species name refers to the peculiar form of the palp in at least the first described species, D. gasteinensis (and D. ramosus), derived from di "two", cranium "head", and palpus. The size of the forked palms are clearly in the photos. Also characteristics of D. ramosus is the way on which it places it's legs when at rest.

D. ramosus is a southern species that has been slowly making its way north over the last few decades. It was first described from Morocco in 1909, and has moved northwards since then. In 1957 it was discovered and described in was first described in Bournemouth in 1957. Thouroughout the 1960s was only found on the south coast, but during the the 1970s and 1980s it spread over the south of England reaching as far north as Leicester by 1989. It reached south-east Ireland in 1994 and spread to north Wales and north-west England throughout the 1990s and into the 2000s.
The map below shows the recorded distribution throughout the UK (2).

1: British Arachnological Society
2: Spider and Harvestman Recording Scheme.

Monday, 2 December 2013

Feeding rush

The winter is coming and the garden is now almost bare of herbaceous plants, with only a few tough stems still poking out of the borders. We've had a number of frosts over the past few weeks which has brought insect hunting to a standstill, but there are a few winter gnats around. So the choice of hunting will be narrowed considerably over the next few months.

Had an invasion of Jackdaws into the garden this morning. Almost like a scene from Alfred Hitchcock's "Birds". I had noticed that the small feeder in the garden was emptying faster than normal, and I now think this might be the reason. The footholds on this feeder are larger than the other one, and allows larger birds to cling on and feed. It's not uncommon for me to see a pair of Jackdaws in the garden, and there are a few pairs in the neighbourhood, but this is the first time I've seen so many in the garden at once. The photos show the queue building up for the feeder.

The collective noun for a flock of Jackdaws is 'a clattering' or 'a train'. I prefer a clattering of Jackdaws, contouring up their calls as they gather on the chimneys and trees surrounding our garden.

The Welsh name, Jac y Do, is not dissimilar to the English name. The English common name jackdaw first appeared in the 16th century, and is thought to be a compound of the forename Jack, used in animal names to signify a small form (e.g. Jack Snipe), and the archaic native English word daw. The metallic chyak call may be the origin of the jack part of the common name,[10] but this is not supported by the Oxford English Dictionary. Daw, first used for the bird in the 15th century, is held by the Oxford English Dictionary to be derived from the postulated Old English dawe, citing the cognates in Old High German tāha, Middle High German tāhe or tāchele, and modern German Dahle or Dohle, and dialectal Tach, Dähi, Däche and Dacha.

Looking closer at the lawn I think there is evidence of their feeding behaviour there as well. Small clumps of moss and grass have been pulled up all over the lawn. There must be some invertebrates in the thatch on which they are feeding. Unlikely to be worms, as they do not pull them out of the ground, but they often feed on worms disturbed by ploughing.

Jackdaws have increased in abundance since the 1960s and more recent BBS data from the BTO suggest that the increase is continuing in all UK countries. Part of this increase over the past 40 years may be due to a reduction in persecution.

The BTO Garden Bird Survey shows that jackdaws are common visitors to gardens, and their reported presence peaks during early summer and again in the autumn. In our garden they are present all year round. A pair nested in next door chimney. Luckily we have a guard over ours to prevent this. But it is not uncommon for the nest to fall apart and drop down the chimney along with the young.