Saturday 29 November 2014

Week 45: Of Beetles, Digested & Rare

A beautiful Oak at the Brickworks

Monday dawned crisp and bright, following the first real frost of the season. Mid-morning, over at the Brickworks, there were still areas untouched by the warmth of the sun, covered in frost and ice.

SE of Baker's Wood, looking north

Frosty Nettles

Shards of ice over the grass

I squelched my way around the site, coming across a few more species of fungi (including Parrot Waxcap (Hygrocybe psittacina) and Golden Waxcap (Hygrocybe chlorophana)). Green Woodpeckers (Picus viridis) were conspicuous and, as on my last visit, a group of Jays were having a hum-dinger of a fight near the entrance track. On my way round, I could hear a small gathering of Fieldfare “chacking” to one another, which I eventually spotted. Bullfinches called softly and it was lovely when a bright, red male, brilliant in the autumn sunshine, flew over my head.

Golden Waxcap (Hygrocybe chlorophana), cap diameter approx 25mm

Having had owl pellets in my freezer for months, it will probably come as no surprise that this week I had Green Woodpecker poo drying on the radiator. It wasn’t planned, honestly. I spotted a very distinctive dropping whilst walking over Dellfield and, after a little research, discovered it was Green Woodpecker poo and that if I found a dry specimen, I’d be able to see that it was packed full of the remains of ants. Well, not one to be put off by the fact that everything was sopping wet from a day’s rain on Sunday, I returned prepared: I bagged up some prime ‘pecker poo and brought it home to dry out.

Wet ‘pecker poo in situ: 35mm long, 6mm diameter

I am mildly reassured that Chris Packham is a fan of Green Woodpecker poo and wrote, “[p]erhaps my favourite bird poo (and I'm sure many other people's too) is produced by the green woodpecker. Again cylindrical, it can be found on short grassy areas where the birds have been foraging. It is about 6-8mm in diameter and somewhere between 25-35mm in length. Its outer skin is white and the interior, visible at either end, is tan brown and roughly textured, so it can look a bit like a crumpled length of a cigarette.

The real joy of woodpecker poo, however, is picking up a dry length and squashing it in the palm of your hand as this reveals the contents as the bodies of countless ants which the bird had eaten, lots of tiny legs and heads and abdomens. Superb.”

Obviously, once the poo had dried out, I was expecting it to crumble into a mass of minute ant bodies and limbs. In fact, it appeared that this particular ‘pecker had been feasting on a smorgasbord of tiny beetles! If I had more time and patience, it is probably possible to identify a few of them from their remains. There are definitely a variety of Weevil carcasses and I did spy the elytra (outer casing) of a 14-spot Ladybird, which was surprising, given how distasteful they are meant to be to birds. Anyway, feel free to let me know in the comments if you can ID any more of them - I’d be interested to hear.

Dried Green Woodpecker poo, split in two. Diameter 6mm

Closer views of crumbled Green Woodpecker poo (scale in mm)

Whilst we’re on the subject of Beetles, the Trust had some very encouraging news last week from Martin Parr (Conservation Manager at Maple Lodge). Earlier this year, Martin had done some informal survey work at the Trust’s Brickworks and Gadespring Cress Beds sites. At the latter, he'd photographed some Bloody-nosed Beetle larvae but didn’t think too much of it until he read Trevor James’ beetle report in the Hertfordshire Naturalist 2014, which contained the following entry:-

"Timarcha tenebricosa Bloody-nosed Beetle. This conspicuous beetle was found on the towpath at Boxmoor, 12th August 2011 D.Hodges. A welcome record of a species that is strangely rare in our county, although its food plant, Cleavers Galium aparine, could not be more common."

Martin got in touch with Trevor and it transpires that the Box Moor Trust’s Gadespring Cress Beds site has the only known colony of this beetle in Hertfordshire! It’s a fantastic record and, thanks to Martin, the site can now be managed in such a way as to enable this rare Hertfordshire Beetle to continue to thrive. If, like me, you're wondering why it's called Bloody-nosed, the answer is that its defence mechanism is to secrete a blood-red liquid from its mouth which irritates the mouth of mammal predators. So, there we go!

Thank you Martin for sharing your time and expertise with the Trust (and me!) and thanks too for providing the information and photographs.

    Bloody-nosed Beetle larva (Timarcha tenebricosa)
    Bloody-nosed Beetle larva (Timarcha tenebricosa)

I'll finish with a couple of shots of the Dellfield Oak.

Taken at 14:40 on Monday, just before Dellfield went into complete shadow, as the sun disappeared behind the ridge of Westbrook Hay

Saturday 22 November 2014

Week 44: Barn Owl Pellet Dissection & Analysis

With just 8 weeks left of this year-long Project, I thought it was about time I tackled the Barn Owl (Tyto alba) pellets I’d retrieved from Box Moor Trust land over the summer. These black, shiny regurgitated nuggets are the Rolls Royce of The-Stuff-That-Animals-Leave-Behind. Just one of these little gems can contain the tell-tale remains of a whole night’s feeding.

Photo: Barn Owl at a rescue centre in Yorkshire, 2009
Like a lot of birds, Barn Owls swallow the majority of their prey items whole: fur, bones, teeth and all. Unsuspecting Field Voles go down the hatch and, initially, into the glandular stomach (proventriculus) where digestive juices get to work. After this, it’s the muscular stomach or gizzard (ventriculus) which acts as a kind of sieve or filter. All the insoluble stuff like fur, feathers, bones etc are retained in here whilst muscular contractions enable the soluble contents to pass through into the rest of the digestive system (small and large intestines and so on). Once the evening’s feed is done, and before further feeding can take place, the gizzard has to be cleared out. It could be up to 10 hours after feeding has finished that the gizzard-shaped pellet is pushed back up through the glandular stomach and coughed up out through the bill. Pellets can be found on the ground at favoured roost sites and, when nesting, the female uses these as her nesting material. There’s nothing like laying your precious eggs in the fetid remains of partially digested rodents! Having said that, I'm the one who systematically collected more than a dozen of these things and lovingly placed them in her freezer next to the sausages. I’ll press on...

Small mammals, most notably Field Voles (Microtus agrestis), make up a large proportion of a Barn Owl’s diet. Reading suggested that one pellet, following a night’s feeding, could hold 4 full skeletons. I was keen to see if this really was the case and what exactly the Barn Owls had found to eat on/around Box Moor Trust land. I got hold of a copy of D. W. Yalden’s “Analysis of Owl Pellets” and downloaded the Pellet Analysis leaflet from the Barn Owl Trust (the images left/right are linked to the info), and set about dissecting a couple of pellets. The results were really very interesting. A special thanks to Martin Parr, Conservation Manager at Maple Lodge nature reserve, for his patience and help in identifying the prey items from the bones. Neither of us had any experience but we gave it a good go (tweezers and magnifying glass essential!).

Barn Owl pellet, approx 5cm long

Ok, so, this (below) is what came out of the (above) thoroughly dissected Barn Owl pellet (I abandoned the second pellet when I realised what a time consuming and painstaking task it was going to be). The bone fragments I couldn't identify are still in the plastic container. Essentially, within a fur matrix and amongst the 500 bones and bone fragments, the pellet very obviously contained at least 4 similarly sized rodents, identified as 1 Bank Vole (Myodes glareolus) (typically 9-11cm long) and 3 Wood Mice (Apodemus sylvaticus) (typically 8-11cm long). Thankfully, this is consistent with published research. Wood Mice are generally one of the main prey items of Barn Owls whilst Bank Voles also feature but to a much lesser extent (see National Owl Pellet Survey Report 2009 for further details). The most notable skeleton bones were 1 upper jaw set/skull, 4 sets of: lower jaw bones, pelvises, shins, thighs, upper arms and skull fragments. There were 3 sets of shoulder blades and forearms and a good selection of ribs, vertebrae, teeth and other likely limb bones. Ultimately, just as the literature suggested, the pellet contained at least 4 small mammals and was likely the sum of a night’s feeding in the wilds of Hemel Hempstead. It's incredible what you can dig out of something created within the digestive system of an Owl!

Approx 500 bones & bone fragments from 1 dissected Barn Owl pellet

I was lucky that the second pellet I half-heartedly dissected contained a Field Vole (Microtus agrestis), the main prey species for Barn Owls. So, I have a set of upper and lower jaws for Field Vole and Bank Vole, and a set of lower jaws for Wood Mouse.

A few photos (scale in mm) and brief notes follow in case they are of interest or use to others. Hopefully, the IDs are correct but, if not, give me a shout.

Bank Vole Jaws

Field Vole Jaws

Comparing Bank and Field Vole jaws

3 cheek teeth in each jaw
Zig-zag chewing surfaces

(UJ = upper jaw; LJ = lower jaw)

Bank Vole Jaws
UJ: no extra loop on second molar (M2) on inner side.
LJ: M2 has loops opposite and
M3 has minor 3rd loop (not present in Field Vole)

Field Vole Jaws
UJ: M2 has extra loop on inner (tongue) side
LJ: M2 has loops alternate and
M3 only has 2 loops on outer edge

Wood Mouse (Apodemus sylvaticus) lower jaw

3 cheek teeth, each with rounded cusps
Lower molars have 6 roots (2 on each tooth) [House Mouse (Mus musculus) has 5 roots; Harvest Mouse (Micromys minutus) has 7 roots]
First molar (M1) has 3 cusps along the front edge
Length of lower jaw approx 15mm (incl. incisor tooth)

Wildlife Explorers (Junior RSPB)

Last Saturday, the children of Box Moor Trust’s Wildlife Explorers’ club dissected 5 of the Barn Owl pellets. It was wonderful to hear how enthusiastic the children had been and that their curiosity and fascination had kept them digging for skeleton treasures for more than an hour. I collected the sum of their findings but haven’t yet had time to examine them in any depth. A cursory glance at the upper and lower jaw bones suggest more Field Voles (Microtus agrestis) and Wood Mice (Apodemus sylvaticus). However, there is one lower jaw bone which is particularly interesting. It has all the features of a Harvest Mouse (Micromys minutus), an increasingly scarce and therefore significant species. It’s a similar length to the Wood Mouse jaw; has 3 rounded cusp molars; 7 roots on those molars (3 on M1), and 3 cusps on the leading edge of M1. My only reservation is that it’s actually 1mm longer than the Wood Mouse jaw bone, which is something of an anomaly. However, assuming the other features are diagnostic, I’ll stick with the initial ID of Harvest Mouse (Micromys minutus), until/unless anyone can persuade me otherwise.

Harvest Mouse (Micromys minutus) lower jaw

3 rounded cusp molars; 7 roots (3 on M1);
3 cusps on leading edge of M1

A = Wood Mouse
B = Harvest Mouse

Harvest Mouse lower jaw
Length = 16mm

This is an exciting record and great work from the Wildlife Explorers. If I uncover anything else of special interest, I’ll be sure to include it in a later post.

Finally, if anyone is planning to dissect an owl pellet, I did discover that although a basic magnifying glass was useful, it didn’t give me enough magnification to be able to pick out the defining tooth features. Photographing the jaw bones with my macro lens was the best way to really see the pertinent details. Also, when the number of roots is significant, I did find that, with care, it was possible to pull the relevant tooth out a short distance (not the whole way) and then photograph the gum line. This enabled me to count the roots accurately.

Box Moor This Week

Although I do seem to have spent most of the week hunched over minuscule bones, clutching tweezers, trying to decipher tooth anatomy, I did escape into the fresh air of Box Moor on Tuesday morning. As temperatures reached around 14 degrees Celsius I shouldn’t have been surprised that a Small Tortoiseshell butterfly was fooled into flight over Fishery Moor. The Oak’s leaves are turning a beautiful orangey, yellow now and, out on the river Bulbourne, the Kingfisher family continue to squabble over territory. The young male was systematically fishing the river on Station Moor, moving from perch to perch, before going back to start all over again. It was interesting to see that the tip of his malformed upper bill looks as though it is in the process of breaking off. A second Kingfisher put in a brief appearance, quarrelled and then flew off east along the canal. The young male resumed fishing, regularly hovering over the water like a humming bird before diving for prey. I never tire of watching Kingfishers…

P.S. If anyone is interested in seeing something of the pellet dissection process, I made a short video here

Saturday 15 November 2014

Week 43: Dapper Caps including Fly Agaric

More fruiting fungi for you this week although lack of brain power means that I shall have to leave the detailed reading up to you, if you fancy it. As a complete fungi foraging novice, it will come as no surprise that at the top of my list of hoped for species around Box Moor was the Fly Agaric. It is the archetypal mushroom with that beautiful white-spotted red cap, and….I had never seen it.

Last Sunday, enticed out by a little sunshine, I drove up to The Old Barn at Westbrook Hay. I hadn’t even reached the car park when I spotted what could only be Fly Agaric, growing by the side of the entrance track. To say I was quite chuffed is to put it mildly and I can understand Pat O'Reilly’s response whenever he finds a specimen, “my heart leaps and I experience yet again the intense feeling of amazement that came over me so many years ago when for the first time I saw this fabulous fungus in a forest.” I guess the sight of it is a bit like walking into a fairy tale. As children, we had perhaps assumed that along with the fairies, Smurfs and frog-princes this mushroom was part of the unseen world of imagination. To be faced with its very real existence, in perfect fairy tale form, is rather wonderful. 

In terms of its place within the wider ecosystem, Fly Agaric forms mycorrhizal associations with many different plant and tree species i.e. it enhances the availability of beneficial nutrients to its host. It isn’t one of the saprobic, nutrient recyclers, from last week. If you’re interested in finding out more, Pat’s article is excellent and well worth dipping into. 

Unfortunately, by Wednesday this week, someone/something had destroyed all of the specimens by The Old Barn. I did find another in Ramacre Wood but that too had been kicked/destroyed.

Fly Agaric (Amanita muscaria)
Cap diameter approx 130mm

 King Alfred's Cakes (Daldinia concentric)
Width approx 60mm
Clouded Agaric (Clitocybe nebularis)
Cap diameter approx 160mm
 Rosy Bonnet (Mycena rosea)
Cap diameter approx 30mm

Monday morning, full of enthusiasm after my fairy tale find, I returned to Westbrook Hay for more foraging. This time I focused on Ramacre Wood. I won’t go into detail about each fungus but will put links in to further reading at the end if you’re interested. The majority of species were recyclers i.e. saprobic (scavengers feeding off and recycling the nutrients of dead wood and leaf matter). A few were mychorrhizal or more specifically ectomychorrhizal. All 3 photographed above are saprobic.

After hours spent in the field, it’s always nice to come across something a little different, such was my luck on Monday. It turns out that there’s a white variant of the otherwise brown Jelly Ear (Auricularia auricula-judae) and it is fruiting well in Ramacre Wood (if “fruiting well” is the appropriate fungi lingo for “there’s a whole lot of it”?!). It isn’t scientifically significant and doesn’t seem to be anything to get particularly excited about (according to this thread) but it was interesting nonetheless.

Jelly Ear (Auricularia auricula-judae)
Width approx 50mm

Jelly Ear & what was previously known as Albino Jelly Ear (Auricularia auricula-judae var. lactea)
Width of largest brown growth approx 60mm

Later in the week, I called in at Roughdown Common and found a few more fungi, a couple of which are included in the photographs below. Walking out onto Further Roughdown, I was greeted by a swirl of Magpies making for the trees, at least 14, a couple of Green Woodpeckers, a Mistle Thrush, Blackbird, a single Redwing and a mixed Tit flock including 7+ lovely little Long-tailed Tits. Over on Bulbourne Meadow, 4 Red Kites came through, circling high overhead, a Kingfisher called and a couple of Nuthatches probed for food in the Reflecting Willow, which, incidentally, has had a hair cut...

Rooting Shank (Xerula radicata)
Cap diameter approx 45mm, height approx 120mm

 [Roughdown] Inkcap sp
Cap diameter approx 30mm
 Deceiver sp (Laccaria genus)
Cap diameter range 30-80mm
 Russula genus
Cap diameter approx 50mm

 Lepista genus, likely nuda or possibly sordida
[Roughdown] Cap diameter approx 50mm 
Armillaria genus
Cap diameters approx 20mm, 40mm
 Conical Brittlestem (Psathyrella conopilus)
Cap only, diameter approx 12mm

The more I learn about fungi, the more I appreciate that getting to a definitive species identification is frequently impossible without microscopic examination or advanced ecological knowledge. I don’t have either of those tools so some IDs are left at the level of genus.

This week’s fungi list with links to further reading

Fly Agaric (Amanita muscaria) [Entrance track to Old Barn car park & Ramacre Wood]
Clouded Agaric or Funnel (Clitocybe nebularis) [Ramacre Wood & Lower Roughdown Wood]
King Alfred’s Cakes (Daldinia concentrica) [Hay & Ramacre Woods]
Rosy Bonnet (Mycena rosea) [Ramacre Wood]
Jelly Ear (Auricularia auricula-judae) [Ramacre Wood]
Rooting Shank (Xerula radicata) [Ramacre Wood]
Inkcap species [top of dell of Lower Roughdown]
Deceiver species (Laccaria genus) [tree covered path NW edge of Bovingdon Reach meadow & Ramacre Wood]
Russula genus [Ramacre Wood]
Lepista genus, likely nuda or possibly sordida [under Oaks, Lower Roughdown] 
Armillaria genus [path south side of Overbourne meadow, Westbrook Hay]
Pholiota genus [Hay Wood]
Conical Brittlestem (Parasola (Psathyrella) conopilus) [Ramacre Wood & path south side of Overbourne meadow, Westbrook Hay]
Hygrophorus genus possibly lindtneri [under Oaks, Lower Roughdown]
Tubaria genus possibly conspersa (Felted Twiglet) [Ramacre Wood]

And, to round things off, it's this week's Oak photograph. Its leaves are well and truly turning now.

Saturday 8 November 2014

Week 42: Fungi Unearthed: Bonnets, Bells, Shanks & More

Dellfield meadow leading up to Hay Wood

Fungi! The stuff of fairy tales and the home of the Smurfs! Who could resist that?! Tuesday morning, I shunned the crisp bright sunshine and sought out the dappled, dank, darkness of Hay Wood, in search of Fruiting Bodies (that should probably be followed by some kind of menacing hallowe’en cackle!). I won’t pretend that I had a clue as to what I was looking at. Everything I know about fungi could fit on the teeny weeny 3mm wide cap of a Frosty Bonnet. But, it was fun discovering all these weird and wonderful eruptions in amongst the musty autumn leaves and rotting stumps of the woodland floor. Above my head, I could hear the many Goldcrests singing away. Wrens too piped up. Mostly, I was absorbed in trying to photograph bonnets, bells, shanks and all manner of imaginatively named growths (full species list at the end).

Velvet Shank (Flammulina velutipes), cap diameter approx 60mm

Conifer Tuft (Hypholoma capnoides)
cap diameter approx 12mm

Crust fungus sp (perhaps Yellowing Curtain Crust
[Stereum subtomentosum]) width approx 20mm

Frosty Bonnet (Mycena adscendens)
cap diameter approx 3mm

Other than providing a comfy seat for posing Fairies or a cosy hearth for a hard working Smurf, fungi obviously play a vital role in the context of the woodland ecosystem. It and bacteria are the primary recyclers of nutrients, breaking down dead and decaying matter into a form which is then readily available for reabsorption. I suspect that all of the fungi I’ve encountered this week fit into this category. Of course, it has other niches, such as the vital mycorrhizal associations with plant roots (see Week 3 for more on that). It’s also a food source for both animals and humans although you definitely want to avoid the appropriately named Funeral Bell. Certain fungi have medicinal use (e.g. Penicillin); whilst others cause disease in plants (like the fungal pathogen Phytophthora affecting some of the trees on the Trust’s moors); others cause disease in animals/humans (Athletes Foot anyone?!). The extent to which fungi weaves its way into our lives is quite striking and perhaps surprising. It seems to live at the extremes of enhancing life or hastening decay and death.

Apart from a forage in Hay Wood, I also took a stroll over the moors on Wednesday morning, ending up at Roughdown Common. A Red Admiral butterfly was fluttering about on Old Fishery Lane. On Fishery Moor, I found what is likely to be Stubble Rosegill whilst, in the dell at Roughdown, I unearthed some lovely Fairy Inkcap (although I rather like its other unofficial common name of Fairies' Bonnets. However, the term Bonnet is more strictly applied to Mycena species, which this isn't).

Fairy Inkcap (Coprinellus disseminates), Roughdown Common, cap diameter approx 12mm

Funeral Bell (Galerina marginata)
cap diameter approx 30mm

Stubble Rosegill (Volvariella gloiocephala)
cap diameter approx 130mm

Candlesnuff (Xylaria hypoxylon)
approx height 30mm

Whilst doing a little reading in preparation for this post, I remembered some photos I took a few weeks back of fungi rings on Preston Hill. I had intended to return when the weather improved and capture both the rings and the autumn trees. Unfortunately, the weather didn’t perk up in time and the mushrooms died back. Anyway, it fits in nicely with this week’s theme. Apparently, when Fairies aren’t dangling their toes off Fly Agaric, they are dancing with wild abandon inside Fairy Rings. Folklore aside, these curious rings of fungi have a very simple biological explanation. They begin with a single spore which beds down, sending out a network of underground roots or mycelium. “Each summer it produces fruiting bodies - mushrooms - which are temporary reproductive bits akin to flower blossoms. The mycelium draws heavily on the nitrogen in the soil as it grows and fruits, and the mushrooms appear at the outer edge of the network, where the nitrogen is richest. As the mycelium network expands, so does the fairy ring formed by the mushrooms. There are two types of fairy rings. Tethered rings are formed by species that are partially dependent on the roots of certain tree species for nutrition, and often occur with a tree growing at their center. Untethered rings don't require tree roots and so are often found in meadows and lawns.” (reference here). I’m afraid I didn’t look closely at the mushrooms forming the rings on Preston Hill so didn’t identify the species. The network of mycelium going into producing that large ring (approx 2.5 metres diameter) must be quite something!

Fairy Rings on Preston Hill 15 October 2014

Another interesting find in Hay Wood were 2 locations where a bird of prey (likely a Buzzard) had spent some time plucking fur from a rabbit (I think). In the photograph below, the bird had perhaps used the raised stump as a means of anchoring the rabbit whilst preparing it.

Ok, a list of this week’s 13 fungus finds with links to further reading if you fancy it:

Angel’s Bonnet (Mycena arcangeliana)
Frosty Bonnet (Mycena adscendens)
Snapping Bonnet (Mycena vitilis) (possible ID)
Yellowing Curtain Crust (Stereum subtomentosum)(possible ID)
Funeral Bell (Galerina marginata)
Velvet Shank (Flammulina velutipes)
Blushing Bracket (Daedaleopsis confragosa) (poss ID)
King Alfred’s Cakes (Daldinia concentrica)
Stubble Rosegill (Volvariella gloiocephala) (poss ID)(Fishery Moor)
Fairy Inkcap (Coprinellus disseminatus) (Roughdown Common)
Conical Brittlestem (Parasola conopilus)
Candlesnuff (Xylaria hypoxylon)
Conifer Tuft (Hypholoma capnoides)

Frosty Bonnet, showing the sugar-like "frosting"

Velvet Shank, showing the...velvety shank

Finally, this week's Oak photograph