Returning Otters

Its quite a while since I last update this blog, but the autumn has been relatively quiet, with wildlife interest restricted mainly to fungi.  Waxcaps are ok but they are not that exciting.

This week has been a little different.   The weather has been challenging; we have had strong winds for over 2 weeks now, with a couple of trees brought down.  But an otter family has turned up. In October and November we had occasional otter sightings, probably a male, but the return of a mother and cubs at this time of year follows the pattern of previous years.

Last Sunday I saw a mother and cub briefly, alerted by the weak piping whistle that cubs make, but on Tuesday we had a 30 minute view of a mother and two cubs.   The cubs were about half the length of the mother and therefore probably less than a couple of months old.   

It was low tide, and quite dark, with the otter family swimming very close to the shore in no more than a metre of water.   Almost a training swim.

The family are using a holt at the cliff - heavy sprainting, a dead dogfish and a well used path - and I have put a trail camera there.

No still pictures of the otters because it was too dark, but I have quite a lot of video to do something with.  

Rain, lots of it

We have had lots of rain recently.   At the weekend, weather from the west meant strong winds and heavy rain.   On one day alone we recorded over 90 mm (over 3 inches) and the a run off stream from the hill behind us became a torrent.  Fortunately it runs steeply and directly into the sea, because otherwise, that ominous forecasters' phrase 'disruptive rain' would be appropriate.  As an aside, forecasters have some intriguing words to describe rainfall; one I heard recently and am puzzling over is 'organised rain', whatever that means.

In fact there have been few dry days recently and the recent poor weather confirms that the best time to visit Skye is either May or October, not in late summer.

There are still a few insects about such as common carder bees and white tailed bumblebees hunkering down on plants against the rain, mainly devil's bit scabious, goldenrod and autumn hawkbit. Fox moth caterpillars are everywhere.

White-tailed Bumblebee

Fox Moth Caterpillar

Besides fox moth caterpillars there are a few other moth caterpillar species such as knot grass and what I think is a ruby tiger moth, (not certain because I have never caught an adult on the croft) which I found during a break in the rain.  

Probably a Ruby Tiger Caterpillar

Knot Grass Caterpillar

A few fungi are also making an appearance.   Needless to say endless work is needed to get anything like an identification of them and maybe I will compile a list in a future note.

The real highlight though has been regular sightings of golden eagles.  A bird perches on the summit of a modest hill, Beinn Reireag Bheag (225m) at the north end of Scalpay, roughly 2.5km away and therefore  a scope is needed to see it.  Typically it sits there almost motionless for 20 to 30 minutes then takes off either to the east side of Scalpay and out of view, or towards Raasay to the north. One day we saw two eagles together in the late afternoon on the thermals.


Incredibly the sun is now shining and so that is all for now and I am off outside.  

Haytime

Over the last couple of weeks it has been 'haytime'.  I have been mowing the grass on half the croft now that the bluebells have set seed.  We are  trying to create a hay meadow replicating I hope, what was done 20 or 30 years ago.  According to the Skye and Lochalsh Haymeadow Report 2003,traditional management of a croft involved a rotation of 2-4 years cropping (potatoes,turnips, oats, oats-undersown) with 7 or more years of grass. The grass was cut annually in late summer to make hay for winter feeding of cattle and horses. The aftermath was grazed in autumn by cattle coming off the hill, then rested in winter before shutting up for the summer hay crop.  Hay meadows are now a rare sight on Skye and indeed elsewhere, having been replaced by year-round sheep grazing or earlier cropping of grass for sileage.  Many crofts have been abandoned to bracken and brambles (and new houses).

Sweet vernal grass

The dominant grasses in our hay meadow are Yorkshire fog, viviparous fescue, common bent and sweet vernal grass with patches of purple moor grass and occasional crested dog's-tail.   Common sedge, oval sedge, starry sedge and green-ribbed sedge are frequent in the damper areas. Soft rush and bracken are the aspirationally dominant plants and have to be kept in check.  More colourful plants include bluebells and pignut in May, and at the moment meadow buttercups (creeping buttercups in the only area that I think was once dug over), and devil's-bit scabious.   This assemblage seems fairly consistent with the 2003 survey.

Rather than gathering the hay up I now leave the grass in place, raking it over a little so it dies down and provides a little nutrient, equivalent to autumn grazing, and it is noticeable that bluebell seeds germinate well under the mown grass.  I disturbed a toad during the cut but surprisingly no field voles.

Areas where the orchids flowered have been left for a later cut in September and October, as they are just at the point of developing seed pods.   I do rake the grass off those areas to keep the level of nutrients low - which is not too difficult - and it seems to benefit the orchids.

There have been no mammals to report, other than a few pipistrelles at dusk.  Reasonably regularly in July and August in the past we have had a sighting of dolphins but not so far this year.   We therefore went up towards Staffin at the north end of Skye where there is a more reliable viewpoint and sure enough we had a twenty minute view of probably 20 or so dolphins (maybe common dolphins but I cannot be certain) in the channel between Skye and Rona.   Too far away to get a photograph - fortunately as I had left my camera at home.   Here is a picture taken four years ago in Loch Ainort of bottle-nosed dolphins

Insects have been the main focus of attention.   Dragonflies are on the wing, a black darter and common dragonfly perched long enough to allow a decent view.

Black darter

Common dragonfly

Common blue

Scotch argus butterflies are everywhere though they do seem to have a preference for the damper areas.   I also found a Common blue butterfly down by the shore.

Scotch argus

Down by the shore there is a little pocket of woodland plants such as wood anemone and I found a few Skullcap plants there.  Feeding on them was what I think is a caterpillar of the Skullcap sawfly.

I nearly forgot; I found another sedge on the croft, pale sedge.   Only a few plants but that brings the number of Carex species up to 8.

Pale sedge

End of a Marathon

I finally finished the orchid spike count last week.  There are still a few stragglers coming into flower but they will be ignored.    It has been a bit of a marathon over several days, labelling each, noting the position and in the case of the butterfly orchids, measuring height, number of flowers and the leaf width.    The numbers are up slightly on last year:  

                                               Flowering spikes
                                                         2013          2012            
Early marsh  (D. incarnata)             76            63
Northern marsh (D. purpurella)        20            18
Heath spotted (D. maculata)         471           380
Heath fragrant (G. borealis)          307           303
Lesser butterfly (P. bifolia)             42            36
Greater butterfly (P. chlorantha)     103          106

The numbers might get slightly revised, once I have tidied up my notes which got wet three times.  

I photographed all the hybrids, noting also the leaf arrangement, and whether the leaves were spotted or not.   There is a selection of photos below.   Most are maculata x purpurella but there were 3 G borealis x D. maculata.   There was also one which defies attribution to parents but nevertheless looks very neat.  

D. maculata x purpurella

D. maculata x G. borealis

D. maculata x purpurella

The 'neat' hybrid 

I am analysing the butterfly orchid data and hope to produce a note later this year, on the features that discriminate between the two species.

I attended a sedge identification course led by Stephen Bungaard under the auspices of the Skye and Lochalsh Environment Forum.  Stephen's knowledge of the plants one might encounter in the area is phenomenal, both in terms of the taxonomy but also plant locations, so the day was extremely useful.

There are 37 species of true sedges in Skye, Raasay and the small isles, 12 of which are described as common, the focus of the course.    7 of these common species occur on the croft:

Oval sedge,  Star sedge, Common sedge, Common Yellow-sedge, Green-ribbed sedge, Carnation sedge, Flea sedge

Common
Yellow-sedge

Flea Sedge

Oval Sedge

Small heath butterflies are commonly on the wing and for the last few days, meadow brown butterflies are around.    Apparently we get a different sub-species in NW Scotland (ssp splendida) to that in the rest of Britain.

I put the moth trap out 2 weeks ago, catching at least 120 moths, then last weekend on two separate nights I got counts of 76 and 130 (a few escaped) including both buff and white ermine, flame shoulder, campion and various carpets.   I am slowly working through the identifications.

I found the first fruiting waxcap of the year, last weekend, probably Vermilion Waxcap (Hygrocybe miniata), growing on the short trampled grass at the foot of a slope.  The cap measures 15mm and the fruiting body was 28mm high. The spores were white, oval and measured 7 micron.

We had only one otter sighting last month - a brief sighting just before low tide.   Nothing this month.

Orchid Invasion

Northern Marsh Orchid

The fields of blue are just a memory as the bluebells have faded and are setting seed.   There is lots of pignut where they flowered but nothing like as spectacular, not helped by some pretty average weather.  

The botanical interest has shifted to other areas of the croft where the soils are poorer (not that any part can be said to be anything other than marginal) and we now have six species of orchid in flower: early marsh, northern marsh, heath fragrant, heath spotted and both greater and lesser butterfly orchids.   There may be a seventh, common spotted orchid, because a few plants have the characteristic long middle lobe on the labellum but I am not sure whether it is not just variability in the heath spotted orchids.   I need to take a closer look.

Over a 3 to 4 week period, the early marsh appear first, followed by northern marsh and lesser butterfly together with a few heath fragrant and heath spotted but the majority of these last species come later along with greater butterfly orchids.   This year the orchids started flowering a couple of weeks later than usual. 

Heath Fragrant Orchid

I have done a count of the orchids in each of the last 5 years to monitor the impact of our maintenance regime.   The croft is not grazed.   The orchid areas are strimmed close to the soil in September after seed set and dispersal, with the trimmings raked off and removed.   Last year there were just under a thousand orchids in total, with hundreds of heath spotted and heath fragrant orchids, though the number of every species has increased year on year.  This year's count is under-way interrupted frequently by rain and midges - clouds of them everywhere.

Heath Spotted Orchid

Early Marsh Orchid

Each orchid species seems to have a preferred niche.   Early march orchids are in the wet, marshy areas where bog asphodel and eared willow are common, and whilst there is some overlap with lesser butterfly orchids the latter seem to prefer slightly drier, low nutrient areas.   Heath spotted are found in both environments but also where there is some heather.   There are differences related to where they grow; in the heathery, moorland-like areas they are paler and have the classic broad labellum but in the wetter areas they are tinged pink and do not have quite the same broad labellum.    There is some overlap between greater and lesser butterfly orchids other than in the marshy areas where there are no greater, but characteristically greater are found in the areas with a deeper sward, often where bracken was previously dominant.   Fragrants are the most catholic as to where they appear.   

I have casually looked at the associated plants and plan to make a more ordered and structured survey this year.   I have also tried to get some indication of soil quality but the commercial garden tests available provide no useful information so I am a bit stuck there.

Lesser Butterfly Orchid

Whilst genetically the two butterfly orchid species are very similar they look different.   Greater are slightly creamier than the paler lesser butterflies, and are physically more robust.   Of course the positioning of the pollinia is regarded as the best differentiator; lesser have two parallel pollinia over a small opening to the nectar-filled spur, whereas the pollinia in greater butterflies are angled widely apart and the opening to the spur is large.   

Greater Butterfly Orchid

I have made a particular study of the butterfly orchids measuring a number of physical attributes for comparative purposes.   All the greater and lesser that have flowered in the previous two years are marked so as well as comparative data I have some interesting stuff on what happens to plants year on year.   Some of the data goes back 5 years.   At the end of this year's count I will summarise the results.  

Hybrid probably Northern x Heath Spotted

There are also some interesting hybrids which can be challenging to assign to parent species.   



I have seen no otters lately and there are no signs anywhere either.   I am hoping Steve and Gill are still seeing them at the other end of the village.   At the start of the month the trail camera was still picking up an otter visiting the 'cliff holt' regularly between 10pm and 4am but I have had to remove the camera because bracken has grown too tall over the otter run triggering the camera in every slight breeze.

White-tailed Bumblebee

Small Heath Butterfly

I was quite surprised to find a white-tailed bumblebee apparently pollinating an early marsh orchid; it is pretty unusual to find any insects on them in the day time.   Elsewhere there were lots of small heath butterflies, suffering like me in the rain.

The Fields Have Turned Blue

Our croft has turned blue.   Something like a third to a half of the croft has bluebells on it and they are now at their best.  Because every single plant is precious we have to tip-toe round them!


 Normally regarded as a woodland species appearing in glades and rides, on Skye they appear in open fields provided there is some deepish soil, areas also favoured by bracken.    Over the last 5 years we have cleared the bracken (and the brambles) by a combination of strimming, chemicals and hand removal.   My fear was that the use of chemicals might also damage the bluebell population but I don't think it has.


To measure the impact, 3 years ago I staked out 2 plots each a square metre in area and have counted the number of flowering spikes in each plot each year since then.    This table shows the results (flowering spikes per sq metre):
                              Plot 1     Plot 2
               2011        106         107
               2012          88           86
               2013        165           94







In terms of croft maintenance we try to replicate hay meadow conditions which was how it was in the1960's (and a past resident remembers clouds of bluebells then).    We use a powered scythe to cut the grass at the end of July down to about a couple of inches (later and shorter where there are orchids) after the bluebells and grasses have set seed.   Up to 2011 we collected up the mowings into hay ricks, but last you we left the mowings where they were (turning them a little) to add a small amount of nutrient back, except for the area around Plot 2 where the cuttings were removed.


Has this made a difference?   Is the significant increase in Plot 1 a result of the new regime?    Certainly too early to tell, but the seed germinates really easily, if it does not dry out.

 Also in flower at the moment is lousewort, marsh marigold, cuckoo flower, heath milkwort, marsh and dog violets and there are quite a number of common carder bees and white-tailed bumblebees, but only the former seem to pollinate bluebells.


In amongst the bluebells are 3 albino plants, a ratio I calculate of 200,000:1!










We have seen no otters recently.   Gill and Steve at the other end of the village have had a few sightings, one of which last week they thought was a male.  There are a few spraints around.

At the northernmost point of the croft lies a really interesting holt..   Under a rocky bluff  is a holt entrance at the shore, and another entrance at the croft side of the bluff.   There must be a cavernous passage from one to the other.   I have had an infrared trail camera on this for a few days and got pictures of an otter using the holt on 3 days between the hours of 22.00 and 04.00, loosely 'nightime' , remembering that it stays light up almost to midnight at this time of year.

Has Spring Been Cancelled?

A rather quiet period recently.    There are no signs of otters, and they seem to have gone.   I looked backed at all our observations over the last 8 years, a total of 69 events, to see if there was a seasonal pattern.   Of this total on 19 occasions we saw two or more otters together including a sighting of 5 otters in December 2010 (mother, 3 cubs and  male).   Below is a picture of the three cubs back then.

There is a seasonal pattern as can be seen in the plot below of sightings by month.



Otters are seen more frequently in the period October to March than they are between April and September (a ratio of over 2:1)  The pattern is even more pronounced for multiple sightings. If there is any bias in the data then it would be towards the summer months with much longer days and ease of observation.

I estimated the date of birth of the cubs we saw between January and March, by comparing their size to that of the adult mother from photographs in January and March and then using a chart of the rate of growth of otters in a paper by C Reuther (IUCN Specialist Group Bulletin Vol 16 Issue 1 11-16).  This information was for captive animals and it may be that wild animals grow more slowly, so that my estimate that the otters were born in late November and we started seeing them when they were 6 to 8 weeks old, might have been rather later than reality and their age understated.




 I also looked at the observation data to see whether there was any preference to the state of the tide, using data from the British Oceanographic Data Centre to provide the time of high tide.  Do otters prefer to fish on a rising or falling tide?   If there is a preference then it is not marked; maybe a falling off as high tide approaches.

Spring has been much delayed and there are very few plants in flower. The celandines and primroses are now flourishing but little else.   A small patch of  Great Woodrush is in flower, growing where I cleared away bracken 2 years ago and will soon be followed by Field Woodrush which is very widespread.  But little else, other than a solitary flower of  Wood Sorrell.

There are though some more hopeful signs.   I heard a cuckoo on Scalpay on 26 April, and other summer visitors have arrived - lots of meadow pipits, a pair of Common Sandpipers, a Wheatear and Stonechat.   In the garden there were queens of both  Early and White-tailed Bumblebees and the Hoverfly, Eristalis pertinax.

Last weekend there were some very low tides.  Moving a buoy anchored to two iron girders gave me a chance to poke around the kelps which was fully exposed.  Lots of Starfish and Velvet Swimming Crabs, and a small rather fat round fish which jumped out when I moved one of the girders.  It was away before I knew what was going on..

Then I fell over and got completely soaked.   The sea is cold!