Early spring in the Derwent Walk Country Park, Gateshead

 Some pictures from a walk last week in the Derwent Walk Country Park, Winlaton Mill, Gateshead.

Silver birches and willows, seen from the top of the Nine Arches railway viaduct over the river Derwent. The buds of the birches take on a purplish hue at this time of year, as they begin to swell, while the willows have an orange tint.

Carrion crow. Handsome birds, with a hint of blue iridescence in their plumage.

A fine display of colt'sfoot

Dutch rush Equisetum hyemale spore cones beginning to disperse spores. An uncommon plant, but there are some fine patches of it beside the footpath.

Golden saxifrage in full flower in a ditch beside the old railway line.

A heron with some fine chest plumes, feeding in the river Derwent.

Beard lichen Usnea sp. Remarkable that this pollution-sensitive species is now established here, when you consider that this was formerly a location for coal mines, an ironworks and the Derwenthaugh coking plant that only closed down in 1986.

A magpie in one of the meadows

Primroses in flower

A soaring red kite

Toads coming out of hibernation in the woodland, heading for Clockburn lake, on the site of the old coking plant

Wood anemones in flower in woodland beside the river Derwent

No wonder most toads return to their breeding ponds at night!

This toad crossed our path when we were walking in the Derwent Country Park near Gateshead on Easter Monday.

When I knelt down to take a photo and put the camera on the ground he attacked it, presumably because he could see his reflection in the lens. Luckily I had a lens filter attached, otherwise he would have made a mess of an expensive piece of glass.

As we walked around the lake we found several more toads, which we helpfully carried across the path and pointed in the general direction of the water. In retrospect, maybe that wasn't such a good idea because when we walked back ........

......... this heron was having the time of his life at an all-you-can-eat banquet of toads and newts.

I guess this is one reason why big migrations of toads, from their hibernation sites to their breeding ponds, tend to take place at night, when herons are roosting.

Wildlife in an old lead mine

Thursday's Guardian Country Diary describes some of the wildlife that has colonised the old disused lead mines at Westgate in Weardale. Many of the industrial processes that took place here (and ceased early in the 20th. century) involved the use of water, to power a hydraulic engine and to separate lighter stone from heavier lead ore (galena). The legacy is an excellent habitat for wetland wildlife which is now a Site of Special Scientific Interest.

I almost trod on this down-in-the-mouth toad, whose colour blended so well with the mosses around one of the shallow pools where it had spawned. You can see the ridge just behind its eye where the poison glands are located, which deter predators.


In this view you can see most of the main site, with Middlehope burn snaking through the valley. In the foreground you can see bridge parapets for the railway bridge that crossed the burn - ore was taken out on railway trucks pulled by horses. In the middle distance, just to the left of the third bend in the burn, you can see a rectangular depression with a pool of water in the centre. This was once a reservoir.

The reservoir is fed by water flowing out of this mine entrance, known as White's Level. The tunnel is just large enough to accommodate a small pony. Some of these mine levels stretch for miles under the hillside but are now lethal because some lead to vertical shafts where miners were winched down in baskets to tunnels that followed lead veins at lower levels in the strata.

The water flows out through a bed of watercress and into...

.... the silted up reservoir, mentioned earlier. This is a great site for dragonflies in summer, and also a breeding site for toads. The retaining wall on the left, like most of the walls of the mine ruins that were constructed from limestone blocks, is excellent habitat for ferns, like .... 



... the dainty brittle bladder fern.

These are ruins of lead mine buildings downstream, with more waterlogged ground. The key elements for plant growth - soluble nitrogen and phosphorus - are rapidly washed from the soil by rainfall and flowing water, so some of the plants that grow here are adapted to obtaining these minerals by other means.




This is marsh lousewort, a partial parasite on the roots of grasses, that connects with their root systems and siphons off their mineral supplies, and ....



.... these are plants of butterwort. Those rosettes of sickly yellow-green leaves are covered in sticky mucilage glands that trap small insects, which are then digested by enzymes secrete by the leaves.



Downstream Middlehope burn flows through the sheltered, wooded valley known as Slitt woods and ....



...... when it reaches Westgate in Weardale flows over a series of picturesque waterfalls into the river Wear.

Toad Spotting

A couple of weeks ago we watched this toad swimming across the Leeds-Liverpool canal near Gargrave. Strange how much spottier its body looks below the water surface......


More toad pictures here.

Toads

This week saw one of the most memorable events of spring around here - the annual return of toads to their breeding ponds and the ensuing cacophony of croaking and orgy of mating that follows. They arrived in their hundreds, crawling out of the woods and over the wet grass to reach the pond where they grew up as toadpoles.

Some just floated on the pond surface, while....

.... others lurked underwater, but all had just one thing on their mind ...

.... finding something to mate with - and this one was so desperate that it tried to mate with my camera.

Somewhere in this writhing mass of toads there'll be a female.

This cluster slowly rotated in the pond for over an hour .... females are sometimes drowned by the lust-crazed males.

At one point this ball of toads had around eighteen individuals clambering over one another. This must surely be one of the most remarkable displays of blind instinct in British natural history. I saw a group of four toads trying to mate with a reed mace seed head that was floating in the water.

Many years ago, mooching around in a second-hand bookshop, I found a copy of Thomas Bell’s A History of Reptiles, published in 1849 when toads were still classified as reptiles. It provides some fascinating early insights into the life of these amphibians. Part of Bell’s purpose was to “shrew that it is.... highly useful, perfectly harmless, inoffensive, and even timid, and susceptible to no inconsiderable degree of discriminating attachment to those who treat it with kindness”, counteracting what he refers to as “undeserved persecution as the victims of an absurd and ignorant prejudice.... Condemned by common consent as a disgusting, odious, and venomous reptile, the proverbial emblem of all that is malicious and hateful in the human character....”.

This is one of the book's wood engravings. Bell provides a delightful description of a toad feeding: “The Toad, when about to feed, remains motionless, with its eyes turned directly forward upon the object, and the head a little inclined towards it, and in this attitude it remains until the insect moves; when, by a stroke like lightning, the tongue is thrown forward upon the victim, which is instantly drawn into the mouth.”

There are numerous old accounts of toads being found alive embedded in the wood of trees or even inside rocks (like the account you can read here), no doubt poorly observed instances of these animals hibernating under rotten logs and under rocks, and Bell describes some cruel experiments that were performed by early naturalists to prove that entombed toads could survive, including artificially embedding them in balls of hard clay or plaster of Paris ...... all of which inevitably led to the death of the toad.

Bell clearly liked toads and provides an account of how toads are easy to tame, citing his own pet toad that would "sit on one of my hands, and eat from the other..."
























He also dispelled the myth that they are poisonous to humans - a long-standing misconception which you sometimes still hear repeated today. At one time it was believed that their bite, their breath and even a glance from those fiery orange eyes could strike you dead. Bell described how there are glands on their back that secrete an acrid liquid that deters predators, but that’s the limit of their toxicity. Bell went on to record how a Dr. John Davy investigated this secretion: “....... a thick yellowish fluid, which on evaporation yields a transparent residue, very acrid, and acting on the tongue like extract of aconite. It is neither acid nore alkaline; and since a chicken inoculated with it received no injury, it does not appear to be noxious when absorbed and carried in the circulation.”
You can see the glands in question - called paratoid glands in the photo above, showing up as the orange-hued ridges behind the eye.


Footnote: Thomas Bell, more than just a footnote in history.

Thomas Bell, a dentist by profession and author of A History of British Reptiles, was a remarkable individual. His personal researches into natural history were so admired that he became Profesor of Zoology at King's College London and he identified the reptile and crustacean species that Darwin brought back from his voyage on HMS Beagle, affirming that the giant tortoises were native to the Galapagos Islands and had not been taken there by pirates - a finding that was later to prove important in Darwin's interpretation of the way in which these reptiles had speciated on the islands. You can read more about him here.
Photo source: http://en.wikipedia.org/wiki/File:Zoologist_Thomas_Bell.jpg

Footnote: Batrachomyomachia

















As with so many natural history books of the period, Bell’s account of the amphibians concludes with a charming tailpiece wood engraving, in this case of a battle between mice and frogs (double-click for a larger image).

It depicts the scene in a Greek poem sometimes said to have been written by Homer (unlikely, apparently) and probably dating from the fifth century BC, called Batrachomyomachia. In the story (there are numerous variations) a frog offers a mouse a ride on its back around its watery habitat but is frightened by a snake, dives underwater and the mouse is drowned. The tragedy is seen by a fellow mouse and a war, that lasts just one day, is fought between the mice and frogs. The goddess Athena calls on Zeus to quell the fighting using thunderbolts (i.e. an air-strike) but that fails and instead she sends an army of crabs (i.e. sends in the heavy armour) to quell the disturbance. You can read a translation of the poem here.

Toadpoles

Most of the toadpoles in our local pond have begun to produce legs now and will be leaving the water within a couple of weeks. In this water flea's-eye-view you can see the nostrils fully formed, as the tadpole switches from gills to air-breathing.

Hundreds of toadpoles are congregating in the shallow, warm water around the edge of the pond, where...

... they surface to gulp air with increasing frequency.

Some parts of the pond are beginning to resemble toadpole soup. Only a tiny proportion will survive to adulthood and make it back to the pond to breed in future years.

Toxic Toad

I found this tiny toad – a juvenile that’s developed from one of this year’s toadpoles – sheltering under a stone in the company of two slugs that were substantially larger than this bite-sized amphibian.

Baby toads like this are not as vulnerable as they look, because their skin secretes a foul-tasting poison that deters most potential predators. Just behind the eye, on either side of the head, there’s a dense area of poison-secreting tissue concentrated in the parotid glands, which are clearly visible as paler, elongated swollen lumps with prominent pores in this alarmed youngster.