Behaviour Notes





Fieldfare being mobbed by other birds

At about 15.00 on 1 Jan 1997 in the garden I saw a Fieldfare fly down from the Lime tree to a bush by the garden pond. The usual nervousness which Fieldfares exhibit in the garden seemed to be compounded by the alarm calls of several other birds particularly a very agitated Coal Tit.

It became apparent that the Fieldfare itself was the cause of the consternation. A group, variously comprising 8 to 13 birds, began to mob the Fieldfare in a similar way to that in which owls are mobbed. The species involved were Robin, Coal Tit, Blue Tit, Great Tit and Chaffinch. They perched about 1m from the Fieldfare whilst directing alarm calls at it. This continued for about 10 minutes, the Fieldfare remaining virtually motionless.

The garden's other birds including several Goldfinches and Blackbirds, whilst not engaged in the mobbing appeared rather nervous, either because of the Fieldfare or the mobbing itself , and they did not resume feeding until the Fieldfare had left the garden.

The fact the Fieldfare was indeed the cause of the alarm rather than some other unseen threat, was confirmed when the Fieldfare flew back up to the Lime tree. The mobbing continued there for another 5 minutes until the Fieldfare flew off.

This was the first Fieldfare of the winter, in the garden so perhaps it was an unfamiliar bird to some of the garden's residents. It is interesting to note that there is some similarity between the colour schemes of the Fieldfare and Kestrel.

On occasion I have noted that the sudden arrival of a Mistle Thrush causes a brief, mild panic amongst the garden's birds which probably mistake it for a raptor.

Something similar may have happened here but instead of the birds "realising their mistake" a mobbing behaviour developed, driven by a momentum of its own. It seems puzzling, however, that such a seemingly inappropriate behaviour should occur in this prolonged and concerted fashion.

House Sparrow kleptoparasitising Starlings

On many dates in May and June 1991 I observed kleptoparasitic behaviour in the garden. A single female House Sparrow was involved, and on a few occasions a male (which I took to be her mate) also joined in.

The House Sparrow would follow Starlings which were probing for invertebrates on the lawn. As soon a grub had been extracted by a Starling the Sparrow would make a grab for it. About a third of "grabs" were successful. On stealing a grub the Sparrow would take it to its nest, presumably to feed its nestlings. This behaviour was systematic and repeated, rather than merely being opportunistic. The Sparrow was clearly targeting Starlings with the aim of robbing them.

Unusual instances of aerial-feeding

An emergence on flying-ants on 20 July 1997 was accompanied by the usual congregation of Black-headed Gulls, Hirundines and Swifts. While scanning through the Gulls I was suprised to see an adult Hobby also feeding on the ants. Baring in mind the fact that a Hobby usually causes great alarm amongst Swifts and Martins, it was interesting that it was ignored.

Later on 3 Jackdaws, 1 Common Gull, 2 Lesser Black-backed Gulls, and 2 Herring gulls, joined in. I understand that this behaviour is fairly uncommon in the latter 2 species.

Two further interesting observations have been as follows:

On several occasions in August 1995 I watched Hedge Sparrows catching grass (pyralid) moths on the wing. These would be disturbed by the bird, which would then catch them at around 1/2m from the ground and then take them to feed its nestlings.

On 13 Aug 1997 I saw a Magpie fly from a nearby aerial to the roof of the house. The Magpie made a slight deviation from its flight path to take a large flying insect (probably a fly). This may have been an intentional sortie after the insect, or may it just have been happened upon it, en-route.

Nuthatch catching nut fragments in mid-air

Several species, which use the nut-feeders in the garden, frequently display great agility and very fast reactions. Blue Tits for example can often be seen flying rapidly down from the feeder to catch a fragment of peanut which they have dislodged.

The speed of reaction required to perform this feat is nothing, however, compared to that which I have seen performed by Nuthatches. While energetically hammering at the peanuts Nuthatches often send pieces in all directions. Without altering their foothold Nuthatches are able to shoot the body very rapidly downwards and catch the fragment (they are invariably successful) before it has dropped out of reach.

These lightning fast reactions have possibly evolved as a consequence of the Nuthatch's mode of feeding. If nut fragments were not caught in mid-air they would probably be lost for good.

Blue Tit building two nests

During March and April 1995 I watched a Blue Tit simultaneously constructing two separate nests - a completed, lined, nest and a second, unlined, nest in a box about 10m away.

On several occasions I saw the female collect moss, fly into one box, collect more moss, then fly into the other box (thus ruling out two females being involved). I got the impression that the male preferred one box (judging by it's display flights), while the female preferred the other - the one which was lined and in which eggs were laid.

Birds sometimes build more than one nest when confused by the close proximity or similarity of sites. This is unlikely to be the case here, however, one box being on a tree and facing east, the other being on the fence and facing west.

Bullfinch eating large number of pyracantha seeds

On 12 Feb a male Bullfinch fed on pyracantha berries which I had attached to a tree near the house. It spent around 5 hours in 6 "sessions" on the tree during the day.

While on the tree it took around 7 berries a minute. The Bullfinch was in fact eating the seeds and discarding the flesh of the berries. Each berry contains 4 seeds, so (assuming no wastage) the amazing total of around 6000 seeds must have been consumed during the day!
"Birds in a Cheshire Garden"