Report for January to March 2008

 

The oldest free-living Buzzard recorded in the UK was a West Hatch Wildlife Centre patient in 1984!

 

Prior to this last record we had 24 Buzzard ringing returns (out of 291 ringed) with survival periods ranging from 1 to 2580 days (median =  264). 66% of these 24 survived more than 42 days – the benchmark time period used by researchers to evaluate the ability of a bird of prey to survive. Distance traveled from the release site for these 24 birds ranged from 0km to 117km (median =  21) and there is no statistical relation between distance traveled and survival time.

We will continue to ring Buzzards to broaden our knowledge of their post-release survival and we are supplementing this with radio-tracking work.

A bit more about Buzzard rehabilitation at West Hatch Wildlife Centre.

West Hatch Wildlife Centre admits a large number of Buzzards due to the abundance of the species in the South West of England. An average of 100 are admitted each year with a variety of problems including head injuries and broken wings but 40% of Buzzards are admitted for undiagnosed reasons or general weakness.  30% of admitted casualties are released.

A quick overview of ringing and marking schemes used by the RSPCA Wildlife Centres

Ringing and marking rehabilitated animals is one way of determining post-release survival.  We are careful only to use techniques that do not compromise welfare or survival prospects.
British Trust for Ornithology (BTO) rings have been used on birds by the RSPCA since 1982 and since then 23,000 birds have been ringed. Feedback can vary depending on the size and behaviour of the species (from less than 1% for Blackbirds to ~10% for Mute Swans). The ringing scheme has provided good records from a wide range of species including Tawny Owls and Mute Swans showing survival greater than 10 years, and a number of Herring Gulls with over 5 years.
Darvic rings are larger plastic rings which are readable in the field. The RSPCA has been ringing Gulls and Swans with Darvic rings for 8 years now with very encouraging results. RSPCA rehabilitated birds have been spotted all over the UK, in many parts of Europe and even on the African continent. Some birds have been sighted multiple times in different areas and detailed ‘life-histories’ have been recorded.
Tattooing and microchips are used on mammals such as Badgers and Foxes. It was through this scheme that we had confirmation of the survival of a released Badger cub some 4 years after release.

32 Swans admitted after the draining of a lake exposes them to a deadly bacteria
Over the weekend of the 5th to the 7th of January we admitted 32 Mute Swans from a recently drained lake in Barry (South Wales). The man-made lake had been drained for dredging work exposing the local swan flock to a deadly bacterium, Clostridium perfringens, that was present in the silt. The drainage of the Lake took place in the first week of January against the advice of Swan Rescue South Wales (SRSW) who were monitoring the situation. Four swans were found dead during the drainage of the lake and a further 6 were found dead or in very poor condition immediately after. Postmortems by the Veterinary Laboratories Agency(VLA) confirmed the cause of death to be the bacterium. SRSW discussed the situation with West Hatch Wildlife Centre and it was agreed that the centre would admit, assess and treat as many of the remaining swans that SRSW could catch, prior to their relocation to a clean lake.

Over the following days 32 Swans were caught and brought to West Hatch. Five of these were sick and had to be euthanased within a day or two of admission but the rest appeared to be healthy.

The relevant council informed us that the artificial Lake was not going to be filled for at least one month which ruled out returning the swans there.  Complications with the availability of a second release site arose and it became apparent that West Hatch would have to locate a new release site for them. Discussion with Natural England took place to access the legalities of releasing the swans away from the found location as normally the relocation of a flock of Swans requires a licence. With the green light from Natural England we proceeded to release the 27 remaining healthy swans at sites near Exmouth and in Somerset.

The incident highlighted excellent collaboration between SRSW, the RSPCA and also the VLA.  In total 54 swans were involved, 15 died at the site, 12 died in care and 27 were released. Of the 32 swans admitted to West Hatch 27 were released. We benefited from the experience gained at RSPCA Stapeley Grange Wildlife Centre as they were involved in a similar incident previously.

Admissions and Releases

Admission numbers were low over the period as is the norm for the time of the year. We admitted 386 animals and released 193 over the 3 month period, with a month by month breakdown shown in the table below. 

Numbers of admissions and releases (Jan-Mar 2008)

	Jan	Feb	March	Total
Admitted	164	112	110	386
Released	92	36	65	193

We admitted a wide range of species over the period, 53 in total, with Guillemots and Mute Swans tied as the most commonly admitted species. The table below lists all of the species we admitted.

Species	No.	Species	No.	Species	No.
Guillemot	76	Herring gull	4	Great tit	1
Mute swan	76	Pheasant	4	Greenfinch	1
Collared dove	23	Black headed gull	3	Grey heron	1
Badger	20	Carrion crow	3	Hawfinch	1
Feral/town pigeon	20	Sparrowhawk	3	House mouse	1
Rabbit	14	Brown long eared bat	2	Little grebe	1
Common buzzard	12	Common pipistrelle bat	2	Little owl	1
Hedgehog	11	Common toad	2	Magpie	1
Razorbill	11	Domestic duck	2	Moorhen	1
Blackbird	10	Domestic/racing pigeon	2	Muscovy duck	1
Barn owl	9	Jackdaw	2	Redwing	1
Wood pigeon	9	Kestrel	2	Robin	1
Otter	8	Peregrine falcon	2	Roe deer	1
Tawny owl	8	Rook	2	Shag	1
Grey seal	7	Blue tit	1	Smooth newt	1
Fox	6	Domestic goose	1	Stock dove	1
Gannet	5	Goshawk	1
Mallard duck	5	Great black backed gull	1