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Bats of the Manor !

Bat night led by John Dobson, 1st July 2004.

Can't say the sun was shining but the moon was. It was a dry pleasant evening. Twenty three members and guests turned out. We walked from the car park along the edge of Hatters Wood and as we approached the Cow Pond the first of six Noctule Bats appeared flying roughly north to south. John Dobson was of the view that these bats were probably leaving a communal tree hole roost to the north of the Cow Pond. One of these appeared to be attacked by a Hobby which twisted and turned in pursuit in the twilight but failed to collect any reward for its efforts.

We moved on to the Lily Pond, but were disappointed with no contacts. After ten minutes or so, we headed back to the Green Pond where a couple of anglers were somewhat surprised to be disturbed by two dozen bat watchers. Numerous Pipistrelle bats were located and seen around the Green Pond. I suspect the fishermen were wondering what all the fuss was about; they must have sat and watched the bats on numerous occasions. John was particularly interested to locate Daubenton's bat on the Green Pond, but if they were around, we never saw them. Daubenton's are often seen in South Weald Park taking insects off the surface with their feet. Anyhow, we left the fishermen in peace at about 10. 30.

A very enjoyable evening. The Friends are extremely grateful to John Dobson for coming over from Danbury and giving us an insight into these fascinating flying mammals.

Del

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More about Noctule Bats........................

We are grateful to John Dobson for permission to publish the following map and text. They were taken from his book

"The Mammals of Essex" it was published in 1999 and is, sadly already out of print.

NOCTULE BAT.....

The noctule is a large bat that has been recorded from most areas of Essex. It is dependent on woodland throughout the year, usually roosting and hibernating in cavities and woodpecker holes of both coniferous and deciduous trees. Roosts are changed regularly during the summer: one study, based in Yorkshire, found the mean number of roost changes for one group of noctules to be fourteen . During roost changes, the unweaned juveniles are carried by their mothers. The noctule can be identified by its sleek, golden brown fur and short, broad ears, characteristics that make it well adapted for fast flight in open areas. Of all the Essex bats, the noctule is perhaps the most easily observed. It is large, emerges before dusk - when it can often be seen hunting with swallows and swifts - and feeds in the open over woodland, pasture and particularly reservoirs, where its high, straight flight is interspersed with steep dives to pursue its insect prey.

 

As the evening temperature falls, noctules feed at lower heights and have been recorded around street lights. The noctule was thought to be common throughout England at the end of the 19th century and Laver (1898) recorded that the species "occurred commonly at Colchester as I believe it does throughout the county". However the number of records has declined in recent years and although still widespread, feeding groups have involved fewer bats than in the early 1980s. At that time, around 200 noctules were counted emerging from an ash tree near Colchester (A. Wake, pers. comm.) and up to 50 could be seen hunting high above Hanningfield Reservoir. A group of up to 30 was regularly recorded feeding over pasture at South Woodham Ferrers until the early 1990s but only smaller numbers have been observed recently. The sighting of a group of noctules is not indicative of a nearby roost, as radio-tracked individuals have been found to fly up to ten kilometres to a feeding area (Mitchell-Jones, 1990). In Essex, during the current survey, only five roosts have been found. Twenty-one bats emerged from an ash tree in Little Baddow, 15 from a sweet chestnut at Thundersley, 15 from an oak at Wickham Bishops, 7 from a poplar in Danbury Country Park and 7 when a cedar was felled in a garden at Kelvedon. Most other records have been made with a bat detector as bats have been observed hunting over suitable feeding areas with recent records coming from West Mersea, Tilbury, Foxearth and Stansted.

 

The future for the noctule, as with other large bats, is unpromising: species that feed on large insects are declining, as their prey is vulnerable to the changes occurring in the countryside. Additionally, roost sites are lost as dead trees are removed from parkland where they are perceived to constitute a danger to the general public. A new threat may be the increase in the population of the hobby, a falcon that hunts until after sunset. In recent years, hobbies have been observed chasing noctules at both Hanningfield and Abberton Reservoirs. An unusual record was of a female noctule with a broken wing, collected at Barkingside on 1st October 1992. The bat had evidently mated prior to being taken into captivity and gave birth to a male juvenile in April, 1993. In February, 1998, both bats were still alive in captivity.

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