More of the Same! (Otter, eagle etc etc)

I put a 12 volt external battery on the trail camera to try to extend the operating time. I got 3 video clips on each of the 9th and 10th early in the morning.   This is the nicest, taken just after dawn on Thursday, April 10  of an otter grooming before heading off over the cliff presumably to the shore.

I must have just missed it - if it did go into the sea - because I was down at the shore at 07.30 am.   I did though see something interesting, an eagle between Ard Dorch and Scalpay.   It circled over to Scalpay and settled on a fence post for a few minutes, tested by gulls who mobbed it, then it flew around 50 yards away, finding something to peck at for a further 10 minutes or so.    It then hopped a few yards away where 7 hooded crows surrounded it, like jackals around a kill, taking turns to attack the eagle's head.    The eagle's reaction was one of disdain, putting up with the nuisance for 20 minutes or so, before it finally flew off over Scalpay.   We think it was an immature white-tailed eagle. It was lightish on the back with a distinctive pale patch on the back just below the neck. Evidence of a white tail was hard to see - early morning and distance being a problem.   I took photos but they were next to useless.

I saw our first returning migrant swallow yesterday (I have not checked but this seems very early) and we had a reed bunting on the feeders. 

Meanwhile despite showers I put the moth trap out on Thursday night with a catch of 19 moths  in total of which there were 5 species,  Hebrew Character, Clouded Drab, Red Chestnut and these two, a Common Quaker and an Early Grey moth.

Early Grey Moth

Common Quaker Moth

Tick Biting Parts

I took a walk over the grazings last Tuesday to Loch nam Madadh Uisge, (literally 'fox water') a small lochan above Luib, where there will be lots of water lobelia later this summer.   Flowering bog myrtle was everywhere and a few sedges and rushes were beginning to flower.   I also picked up my first deer tick of the year.   Potentially they can carry Lyme disease.   I used to spray ticks which had bitten into my flesh by spraying them with after shave (or cheap perfume, if closer to hand). The alcohol solvent causes them to loosen their grip and they can be picked off with tweasers.   However the local chemist in Portree cautioned against this approach because the spray can cause the tick to vomit and increase the risk of pathogens entering the bite.   So now I use a little prong which slides under the tick and a quick twist then removes it.  I have lost the packaging but I think the brand name is the O'Tom Tick Twister. It works most of the time but is far less satisfying than seeing the tick visibly unhappy with the alcohol spray, and the chance for some serious revenge.

Early Spring Wildlife

In the day time sightings of otters have been scarce.   3 weeks ago I saw a family, mother and 2 cubs,  bring a large dogfish on shore but then I lost them.  I may have disturbed them because I did hear the alarm call - 'hah, hah' from the rocks though I could not see them.  That was the last sighting but the trail camera has been more successful.   I put an external battery onto it and changed the video setting to record for 30 seconds.   Two nights ago it picked up a single otter on 5 occasions - here are two clips:

If they don't play, then the You Tube links are:  http://youtu.be/YYWDs6O7PAw and http://youtu.be/L-wp_61IR4Y

In flower are the first of the primroses and bilberry.   There are a few queen white-tailed bumble bees ambling about rather sluggishly.

We saw two sea eagles high up over Scalpay this morning whilst yesterday there was a large group of red throated divers together with mergansers, shag and a single black guillemot.

Towards the end of March there were several dry, but cold nights, so I had the moth trap out.   The absolute number of moths caught and the species count were low but after lots of rain it was good to see what was about.   Nothing special but here are 5 of the 6 species caught:
  

Hebrew Character

Red Chestnut

Clouded Drab

Red Sword-grass

Yellow Horned

Now it is time to see if there is anything else about outside!

Nearly the Spring Equinox

Approaching the Spring equinox the days are getting longer, and as a result it is easier to see otters in daylight.   The trail camera recorded a female otter on the 2nd of March and again on the 7th by the cliff holt. There were also a couple of brief night-time appearances.  Below is the female on the 7th.

The holt seems to be a resting place; there are three paths to it from the shore, fairly heavily used given the amount of flattening and regular spraints and bones along the paths.   It is at the top of a small cliff and the entrance faces landward.   There is no fresh water nearby for an otter to wash off sea water.

Below is a sketch, not to scale, showing the paths around the holt - two involve a scramble up the cliff, whilst the third leads down more gently to the shore.   The centre picture is the entrance to the holt whilst the picture to the right shows one of the otter runs.

It has been wet and windy again recently and the ground is sodden.   I really need to be able to work on the vegetable plot but I will sink into mud at the moment.

More nocturnal otter activity

I have not seen any otters in the day time since early January but the trail camera continues to capture night-time activity.   Last night an otter was scratching its ear by the entrance to the cliff holt at 19.45 pm and again at 02.07 am.   Only a single otter, and I cannot be sure whether it is male or female.   It comes to the holt every two or three days.   The family we had in early January seems to have gone.

 The first signs of spring are everywhere - catkins on hazel, willow in bud and earlier this week the first frog spawn on the pond I made in the garden.   The timing is consistent with previous years, mid February to early March.

An Otter Getting Comfortable!

I got an excellent clip last night from the trail camera (I found out that it works best with batteries that are not flat after 3 days with no pictures!).

This is an otter gathering bedding at the cliff holt.    All the recent otter activity has been at night, often in the early morning.    It seems to rest up in the cliff holt, spending several hours there.

Greater and Lesser Butterfly Orchids: Survey Results

There is very little to comment on at the moment;  the otter family seems to have disappeared and I have picked up nothing on the trail camera.  There are though some spraints by the slipway.   There are a few mergansers and great northern divers about, common seals and the occasional curlew and I saw a couple of bullfinches in the garden last week (new to us), but it is quiet, so much so that I have been photographing mosses, which I know virtually nothing about.

This post is therefore a look back to last summer and beyond.   Over the last 2 months I have brought together and analysed 6 years of data that I have collected on the two butterfly orchid species that grow on the croft.   Lesser butterfly orchid (Platanthera bifolia) and Greater butterfly orchid (P. chlorantha) are at a molecular level almost indistinguishable, yet they are still considered separate species and they certainly look different. The former is whiter and less creamy than the latter but position of the pollinia which carry pollen is the most telling way to discriminate between the two:- wide apart in greater, parallel and close together in lesser.

  

  

                                              Lesser butterfly orchid                      

                Greater butterfly orchid


On the croft the two species grow close together and in some patches they intermingle, which is unusual and gives scope for comparison with some of the environmental variables such as climate, nullified.

There is a degree of introgression, making the pollinia test to discriminate imprecise.

Lesser and Greater butterfly orchid plants growing less than 1 metre apart.









The data that I have gathered show statistically significant differences as follows:

a) Lesser butterfly orchids flower 7 - 9 days earlier than Greater butterfly orchids.
b) Height of the flower spike: Lesser average 17.2 cm, Greater average 25.3 cm
c) Width of the lowest of the 2 basal leaves: Lesser average 2.4 cm, Greater average 3.2 cm
d) Spur length: Lesser average 1.6 cm, Greater average 2.5 cm

Summarising, Greater butterfly orchids are more robust than Lesser butterfly orchids, a finding that is not always recognised in the literature.

The seed set efficiency, the number of flowers developing into a seed pod, appeared to be governed by environmental factors especially climate, and slug damage (a significant problem in 2013) rather than any interspecies difference.  Seed set in lesser butterfly orchids was fairly consistent year on year with on average 26%, whereas for greater butterfly orchids the average was 31%, but there was much more yearly variability. In some years the seed set efficiency was statistically significantly different, but in other years it was not and environmental factors, such as slug damage in 2013 seem to mask any difference.



Lesser butterfly orchid seed pods




                                Greater butterfly orchid seed pods




I found no difference in the number of flowers on the spike (Lesser average 12.3, Greater average 10.6, the average reduced by unusually low numbers in 2013 because of late flowering and slug damage)

I looked at the growing conditions.   Soil pH, ground slope, soil temperature and moisture content were not significantly different though equipment limitations might have masked differences.  There was though a difference in the sward height - the height of surrounding plants.   Greater butterfly orchids were commonly to be found where the sward was higher than the plant, whereas lesser butterfly orchids seem happiest in areas with less competition, though there is overlap.

So are they different species?   Morphology would suggest they are, and my data shows that there are differences in the physical size of the two orchids as well as the pollinia positioning differences.   But I am not so sure, and it may be that one is just a bigger version of the other, adapting to different habitat conditions.

The number of flowering plants has grown year on year.   The orchid areas are either mowed or strimmed once a year in early September, after seed set and dispersal, perhaps with some further strimming in the winter if the weather has been mild.

Year	P. bifolia Lesser butterfly flowering plants	P. chlorantha Greater butterfly flowering plants
2008	6	8
2009	8	25
2010	18	38
2011	20	67
2012	35	105
2013	41	104

A few plants have flowered every year for 6 years; by contrast some flower in one year but do not reappear the next (though occasionally they may flower in a subsequent year).

I looked closely at the plants which flowered for the first time in 2012 comparing those that only flowered in that year with plants that flowered again in 2013.   17 new Lesser butterfly orchids flowered in 2012 of which 11 flowered again in 2013, and 6 either produced only a leaf or nothing at all.   I could find no statistically significant differences between the two groups (height, leaf width, number of flowers, seed pod development) though of the plants that flowered in both years, the leaf width was greater in the second year than in the first.

Similarly with Greater butterfly orchids.    There were 59 new flowering plants in 2012, of which 22 went on to flower again in 2013, and the remaining 37 produced only a leaf or nothing.   There were no statistically significant differences in the average height or number of flowers of the two groups, but the average leaf width in 2012 of the plants that went on to flower again was wider than for those that did not.

If anyone is interested in a more detailed account, please get in touch.

Otter Images on a Trail Camera

I have had the trail camera out next to the landward side of the cliff  holt for over a week now.   It works on infra red so there is no disturbance to the animals.

The images aren't great as the otters are coming down, or going up a slope and the camera was too close.   I have now moved it a few feet back.  Here though are a three pictures.

We had one visual sighting of the otter family during the last week, briefly and at high tide, but the trail camera has picked up the otters on 8 occasions:

30.12 17:28 Saw them near the shore an hour earlier
31.12 14:56
1.1  16:01 and 18:21  Probably resting up in the interval
2.1   05:35 and 07:56  Probably resting up in the interval
2.1   18:02
3.1   6:32
Only 2 daytime occurrences, the other 6 after dark.