Rodenticides and local wildlife

(c) S. Allen

Simon Allen of the Gower Bird Hospital wrote: ‘In July 2011 we were called out to a Red Kite near Gowerton, reported as being caught up in a tree by its wing tags. When we arrived the bird had fallen from the tree and was moribund.  It was a young male, one of two kites hatched on Gower peninsula that year. Examination of the bird revealed no signs of trauma around the patagia of the wings, so entanglement was unlikely. It appeared in good physical condition weighing in at 849g, so was sent off for toxicology tests under the Wildlife Incident Investigation Scheme (WIIS). The results stated the cause of death as a ruptured liver due to trauma. Background testing for rodenticides (anticoagulants) demonstrated that the bird had three second generation anticoagulant rodenticides (SGARs) in its liver, these being:

Difenacoum (0.16mg/kg): The first second generation anticoagulant to be introduced in 1974.

Bromadiolone (0.016mg/kg): A second generation anticoagulant. One important attribute appears to be that it does not markedly reduce the palatability of baits in contrast to other anticoagulants.

Brodifacoum (0.002mg/kg):  One of the most potent second generation anticoagulants introduced commercially in 1979. A lethal dose can be ingested after one feed. This product is licensed for indoor use only.

Rodents have developed resistance to the first generation of anticoagulant rodenticides (FGARs) such as warfarin, so new chemicals have been developed.  Both FGARs and SGARs work in the same way, by preventing blood from clotting and thereby inducing haemorrhaging, but their toxicity is very different. FGARs are described as short-acting, they stay in the body for a relatively short time and often require multiple doses to exert their toxic effects. SGARs only require a single dose to cause clinical signs of haemorrhage and they stay in the body much longer than FGARs, increasing the chance of secondary poisoning. Most cases of toxicosis of non-target species involve SGARs

Although cause of death of the kite was recorded as trauma, the report suggested that the residual rodenticides would have exacerbated the injury where otherwise the bird may have recovered (although the bird may have been already weakened by the poison which resulted in the fall and consequent trauma).

Rodenticides may also have a non-lethal effect on a population, affecting their ability to hunt and breed successfully. A study on the effects of rodenticides on a great bustard population in Spain demonstrated a link to increased pathogen and parasite burdens in birds exposed to rodenticides.

It’s not just the top predators such as raptors and mustelids that are being affected. Gower Bird Hospital supplied 20 hedgehogs that had died to a survey for anticoagulants as part of a PhD study by Claire V. Dowding at Bristol University. 85% of the 20 hedgehogs had rodenticide residues in their livers, 15% had the same profile as the red kite i.e. three residual SGARs in their livers. The hedgehogs came from a wide geographical area across South West Wales.

Just like the link between insecticides and parasitosis in bees, the effects of rodenticides on avian and mammal health and fecundity are real and happening now outside your back door.’

Grey day at Bluepool

Bluepool Corner

The walk along the coast past Bluepool Corner was relatively sheltered from the bitter south-easterly wind this morning and even though the threat of snow eventually materialised as rain the ground was still frozen solid! Birds were relatively thin on the ground, but two Short-eared Owls flushed from an area of Bracken made up for this, with other noteworthy sightings including 13 Fulmars on the cliffs (with 9 of these on the cliffs shown above), a Great Northern Diver on the sea and a flock of Dark-bellied Brents feeding on the beach below Twlc Point.

Neil looking almost monastic in the remains of
The Church of St Cenydd on Burry Holms

Very little was seen on-and-from Burry Holms the pick being a few Common Scoter, a Red-throated Diver and a lone Harbour Porpoise. When leaving I collected a few moss samples from the remains of The Church of St Cenydd and we couldn't help wondering what life must have been like for the monk that lived there and what sights he must have seen! A little botanical interest was provided here by the small rosettes of Sea Stork's-bill (Erodium maritimum) growing on the wall tops. The morning was rounded off with two confiding Choughs feeding in the car park at Broughton following a swift walk back to beat the rain, bumping into Chris Brewer on the way.

Pesticides blamed for bee decline

There was a very interesting article in this Sunday's Independant, this excerpt gives a flavour '...Researchers found that bees deliberately exposed to minute amounts of the pesticide were, on average, three times as likely to become infected when exposed to a parasite called nosema as those that had not. The findings, which have taken more than three years to be published, add weight to concern that a new group of insecticides called neonicotinoids are behind a worldwide decline in honey bees, along with habitat and food loss, by making them more susceptible to disease....' 
Clearly it's not just bees that are being affected!
Click here to read the full article.

Deer at Whiteford

[length 55mm] (c) R. Colley

Rob Colley wrote: 'This Whiteford-resident fossil was picked out of a recently-exposed peat slab on the beach at Whiteford point. Cardiff Museum Palaeontology Dept. have identified it as “the lower jaw back (or second) molar of a deer (possibly Red deer), deposited between 3000-11000 yrs ago. These (peat) beds built up in the low lying marshy ground behind coastal dunes… when … sea level was up to 25m lower than today.”

Maybe not all change down there can be attributed to sheep and quad bikes?'

Iolo talk

Iolo Williams is a Patron of Gower Bird Hospital and we are delighted that he has agreed to do another illustrated talk to raise funds for the Hospital. The talk is called “Wales – From Mountaintop to Sea” and will be on Wednesday 1st February 2012 at 7.30pm at The Grove Lecture Theatre, Singleton Campus Swansea University. Admission is by advance ticket only, tickets are £10 each and all funds raised will go towards the running costs of Gower Bird Hospital.

This is a very popular event and there are still some tickets available for purchase at the bird hospital reception on Sandy Lane. Tel: 01792 371630.

Neath Canal Bridge

A total of 17 mosses and 17 vascular plants were noted growing directly on the stonework of the canal bridge downstream of the lock at Crugau yesterday. There was nothing particularly rare or unusual about this assemblage, but I always find it remarkable what can be found once you start looking... 

The neat domes of Grey-cushioned Grimmia (Grimmia pulvinata) were noted growing with more sprawling mats of Thickpoint Grimmia (Schistidium crassipilum) on the top of the bridge parapets. Capsules of Clustered Feather-moss (Rhynchostegium confertum) growing on the wall sides were immersed in water droplets creating an interesting effect and Verdigris Tufa-moss (Gymnostomum aeruginosum) was noted growing along the mortar lines.

Enjoying these patches of winter green was a Two-toothed Door Snail (Clausilia bidentata).

Early Bombus hypnorum

(c) C. Hipkin

 I noticed a Bumblebee on the patio this morning, it was pretty messed up after a heavy downpour. Clearly a recent emerged Bumblebee that may have been caught out by last night's cooler temps? When I went to pick it up I noticed a small amount of movement in its legs. I'm not sure where I got this info from, maybe read it somewhere or Nigel Ajax-Lewis told me, but you can give Bumblebees a much needed energy boost by letting them feed from honey?

The Bumblebee was put on a bit of kitchen towel with a small amount of honey, covered with a plastic tray and placed on the windowsill which gets the morning sun. About 90mins later it was ready to go. The top photo, taken by Charles Hipkin, shows it not long after release in tip-top condition.
On a more serious note it wasn't that long ago that Bombus hypnorum was first recorded in Glamorgan, less than two years ago I think, but the early emergence and long flying season is allowing this Bumblebee to spread like wildfire across British Isles and is sure to be one of our most common Bumblebees in years to come. I like them, not least because they're distinctive among other Bumblebee species!!