Category Archives: birdwatching

Social distancing

In the future I hope we’ll look back on the Covid-19 pandemic as the threat to global health and economics that could have been much worse.

Now, just over a week into a lockdown, we’re still several weeks away from the peak of infections in the UK and it’s beginning to feel like a dystopian dream.

Normal life is suspended for the moment. Everyone who can work from home is doing so. I spend large parts of my day on video conference calls.

There’s a suspicion that some taking part with ‘audio only’ may still be in their pyjamas ūüėČ

Or they might just have a slow internet connection … who knows?

Putting the remote into remote working

I’m fortunate to have a job that means I can easily work from home. I’m also fortunate that it involves quite a bit of writing and thinking, not necessarily in that order.

We’re all keyboard warriors now

And you can write and think when the weather is bad, or during the night.

Which means I’m getting to see a whole lot more of this spring than I’ve seen of any spring for the past 30 years.

The lockdown came into force before the spring migrants arrive but after most of the winter migrants have departed. The fieldfares and redwings are long gone. The swallows and house martins are still a few days away.

But the local frogs have already spawned …

Frogspawn – early March 2020

… and the tadpoles that subsequently emerged completely ignored the recently introduced rules about social distancing.

However, once the remainder of the yolk sac had been eaten the individuals spread throughout the pond and followed the even stricter guidelines which now preclude more than two meeting.

This little pond wasn’t used by the frogs last year, possibly because it is transient and disappears unless there’s a reasonable amount of rain. According to the SEPA rainfall records from Tobermory (the closest recording station) both December and January were unusually wet, with about 150% the usual levels of precipitation.

Tobermory monthly rainfall records

But February was unusually dry (not something you often hear said about Ardnamurchan) and that’s when the frogs would have been congregating to spawn.

Whatever the reasons, there are hundreds of tadpoles in residence this spring. The pond is adjacent to an outside tap (fed from a burn up the hill) so, should it remain unseasonably dry, I’ll periodically top it up as I watch the froglets develop.

One period of exercise a day

As recently noted by Tom Bryson, with a population density of only about 4.5 people per square kilometre, social distancing is relatively easy on Ardnamurchan. The roads are even quieter than usual as there’s a near-complete absence of tourists.

I use my bike to get out and about. With one notable exception this is a perfect mode of transport on the peninsula. You can stop anywhere, for a minute or an hour, with no danger of blocking a passing place. There’s ample time to view the wonderful scenery and wildlife but you also cover a reasonable distance so get a wide variety of views as well.

The exception is the hills, of which there are several.

Kilchoan to Acharacle profile

An unexpected advantage of social distancing is the solitude it has brought … no one can see me wheezing up the gentle gradients at a snail’s pace, or gasping like a cod out of water on the steeper stuff.

But it’s worth it.

Maintain 2 metres distance from others

At the beginning of the lockdown there was an influx of caravans and camper vans as people ‘escaped’ the cities – either taking advantage of enforced time off work, or avoiding regions with high numbers of Covid-19 cases.

Covid-19 notice

Unsurprisingly this was discouraged. Sparse rural communities tend to lack the healthcare infrastructure needed for resilience and, being at the the end of supply and delivery chains, limited resources to support visitors 1.

There is another disadvantage of being on a bike. You see the rubbish discarded by others littering the ditches or in parking areas.

One thoughtless visitor decided to discard the contents of their portable barbeque in the parking area overlooking Camas nan Gael, together with some unwanted food, dumping it right next to the sign about protecting rural communities.

Leave nothing but footprints … and potatoes and charcoal.

Thanks a lot ūüôĀ

Spring is sprung

One of the things you notice on a bike is the influence of local geography on the pace of seasonal change. The first primroses I saw were on very sheltered south-east facing banks over Camas B√†n. Soon they’ll be everywhere … not least because deer don’t eat them 2.

For the first time I also noticed that the slopes above these primroses hold old coppiced hazel woodland, very different from our usual birch, alder and oak. This is something I’d have never noticed speeding past in the car.

Coppiced hazel near Camas Bàn

As I write this the hazel catkins are still present and the leaf buds are just breaking. The deer – bless ’em – have yet to discover the hazel I’ve planted, but have already decimated some of the willow.

Alder buds are also close to breaking and the larch still have tightly packed clusters of needles looking like small green anemones along the branches.

With a bit more time I’ve also noticed differences in the Ardnamurchan birdlife. Siskins have reappeared again in good numbers. For a period they were absent, presumably because there were better food sources in cones on the conifers.

Siskins

The birds are carving up their territories and laying claim to nesting sites around the house and garden. Most of the nestboxes appear to have regular visits, but there’s little evidence of nest building activity quite yet.

Finally, I’ve noticed how the wind direction seems to influence the views I get of raptors. On days with southerly or south easterly winds I’ve seen good numbers of buzzards, sea eagles and ravens (which I consider an honorary raptor) passing, together with one stunning male hen harrier slip-sliding past at close range. In contrast, the more normal westerlies, give regular (but distant) views of golden or sea eagles over the Morvern hills. In late February I watched three pairs of golden eagles together over Beinn Ghormaig, a fantastic sight.

More of the same

It’s looking as though this lockdown will be in force for at least three months. After that there will probably be an extended period with variable restrictions in place. The outbreak-control modelling by Neil Ferguson and colleagues at Imperial College shows these may be needed for many months. There may also be geographic variation reflecting local flare-ups or pressure on healthcare services.

Whatever happens, it is likely to be a very strange and unsettling experience. One of the small benefits will be the increased time we have to appreciate the natural world around. This will carry on as it always has … we’ve just been too busy to notice it.

With fewer cars, visitors, planes, light pollution and noise we might even be able to see more of it. A friend in Edinburgh noted he’d heard the dawn chorus for the first time in two decades due to the reduction in traffic noise.

Western skunk cabbage, Glenborrodale, March 2020

These small pleasures are the silver lining accompanying the cloud we’re currently under.


 

The birds of Ardnamurchan

Blue tit

Ardnamurchan has excellent birdwatching. In a relatively small area it has a variety of habitats – mountain, moorland, all types of woodland, raised bog, coast, sea and freshwater lochs, machair and just about everything in between.

Bird Watching magazine published are article on birdwatching on Ardnamurchan¬†in 2013 calling it Scotland’s Hidden Gem.

I’m an amateur, but enthusiastic, birdwatcher. Like many birdwatchers I try and keep a running¬†list 1 of what I see locally (my patch) and on my travels.

I’m not a twitcher. I don’t chase rarities, I don’t keep monthly, annual or geographic records. I’m hopeless at discriminating between most of the Phylloscopus¬†(leaf) warblers (and gulls 2). I do however have a vague idea of the – very extensive – list of UK birds I have never seen and enjoy reducing the number when I have the chance.

It’s always good to know what¬†might be seen in a particular area i.e. what has been seen before and is therefore likely to turn up again.

Or that’s there all the time if I was only a bit more observant ūüėČ

The BTO open mapping bird atlas data

Fortunately, thanks to thousands of volunteers and the British Trust for Ornithology, there are outstanding records of overwintering and breeding birds for the entire country. This dataset now contains ~1.4 million records covering ~450 species between 1968 and 2011. It is updated every couple of decades.

This data is at 10 km resolution (i.e. was a bird present / breeding in a particular 10 km square?). More recent surveys have been conducted at much higher resolution (based upon 2 km tetrads) and now include ~20 million records covering 99.9% of the country.

Until recently this data was only available in book form, but the 10km resolution data is now freely available online. For any species you can view a map of the UK showing if and where it is present in the winter, and whether it possibly, probably or definitely breeds here in the summer.

BTO bird atlas mapping

Inevitably, the maps are rather low resolution. You can just about see Ardnamurchan, but it’s not obvious. The BTO also offer a variety of other ways to view the data, such as providing lists of birds by¬†searchable map reference or postcode.

Local lists of local birds

Not only can you query the dataset interactively, you can also download the bird distribution data as compressed ZIP format comma-separated variable (CSV) text files. Uncompressed the files total about 125Mb. The largest is the geographic and temporal distribution data which runs to ~1.5 million lines. Don’t try opening it in Excel (which is probably the default for this file type on your computer) as it can’t cope with more than ~1 million rows 3.

A wet spring weekend seemed like the ideal opportunity to generate an Ardnamurchan-specific bird list. CSV files are trivial to manipulate using a simple scripting language such as perl or python. What could possibly go wrong?

10 km resolution

Of those 1.5 million records, only a subset are relevant to Ardnamurchan. The rest of the country we can safely ignore.

The first challenge is to determine which 10 km squares overlay the ~30 km x ~10 km Ardnamurchan peninsula. The BTO uses the same grid overlay used by the Ordnance Survey and the latter provide a very useful tile locator map. If you select the relevant 100 km square (NM) you are taken to a more detailed view showing the individual labelled 10 km squares.

Ardnamurchan 10 km map squares

Ardnamurchan 10 km map squares

The numbering of these squares represent the first digits of the Eastings and Northings coordinates of the grid reference. For example, Acharacle primary school is at NM 674 681 and is in the top right hand (north west) corner of NM66.

NM47, 57, 67, 46, 56, 66 covers Ardnamurchan in its entirety 4, together with bits of Muck, Moidart and a small wedge of Morvern. That’ll do.

Big(ish) data

For the moment the only two data files that are of relevance are the lookup table of species (species_lookup.csv) and their distribution (distributions.csv).

species_lookup.csv has four fields, the unique species code (an integer 5, the common and scientific name(s) and an indication whether it is a distinct species or an aggregate 6.

distributions.csv has eight fields including the survey period, season, species (the id number only), 10 km reference square and whether breeding was possible, probable or confirmed. I’ve ignored the additional fields for the moment. With ~1.5 million lines in the file there are multiple records for each 10 km square and for each species.

Siskin (male)

Siskin (male)

For example, there are 2082 records for the six 10 km squares covering Ardnamurchan and 9290 records for the Barn Owl (Tyto alba) covering the entire country.

Of these, only seven intersect. The Barn Owl is present in five squares during the winter, but breeding is only suspected or known in NM67 and NM56.

This doesn’t really qualify as ‘big data’ but untangling it is too much to handle with just a pen and paper 7. Instead, it’s a trivial exercise to spend a wet afternoon (when I couldn’t do any beekeeping) writing some perl scripts to extract the relevant records for presentation.

Data mangling and untangling

The historical information in the BTO Bird Atlas data is of less interest to me (at the moment at least 8). I’m interested in the most recent reports from the winter and breeding season records … these are the birds I (and visitors to Ardnamurchan) are most likely to see now.

Maclean’s Nose … a good spot for white-tailed and golden eagles

Following the usual cycle of code, debug, coffee, code, debug, coffee pizza I had something that just about worked.

A total of 143 species overwinter, breed or both on Ardnamurchan. Of these, 26 (mostly overseas migrants like the cuckoo and willow warbler) are absent in winter. In contrast, 34 species are either absent in the summer or do not breed on Ardnamurchan.

Unsurprisingly considering the limited land area present in NM47 and NM57, these 10 km squares have the smallest number of summer or winter species:

  • NM47 – winter 59, breeding 56
  • NM57 – winter 49, breeding 48
  • NM67 – winter 83, breeding 89
  • NM46 – winter 66, breeding 89
  • NM56 – winter 77, breeding 81
  • NM66 – winter 103, breeding 90

It’s worth noting here that presence alone in the summer is¬†not recorded for any species on Ardnamurchan. Just because a particular species does not breed does not mean there is no chance of seeing it 9. For example, I’ve¬†regularly¬†seen gannets in Loch Sunart though they don’t breed on the peninsula.¬†

Data presentation

Having sliced and diced the BTO data it now needed to be presented in a readable format.

Rather than just present a ‘flat’ list of birds it seemed logical to include links to relevant information online. For example, to the BTO Bird Atlas maps of the entire UK for the winter and breeding season distributions and to the BTO Bird Facts data.

This turned out to be a little bit more complicated than it should have been. The BTO appear to use two different numbering schemes.

Species in the BTO Bird Atlas use a taxonomically-organised sequentially-numbered list of UK species. I’ve mentioned the red throated diver (#1) and Blue-crowned Parakeet (#1663) previously. In contrast, the Bird Facts pages are referenced using the 5 digit EURING code used by bird ringers. The EURING code for the Red throated diver is 00020 10.

Initial attempts to find the Blue-crowned Parakeet on the EURING list failed which highlighted a second problem 11. The scientific names (the only sort of names used) on the EURNG lists are sometimes different from the BTO lists. This happens when birds are reclassified. On the BTO the Blue-crowned Parakeet is Thectocercus acuticaudatus whereas EURING lists it as¬†Aratinga acuticaudata. D’oh!

Entirely the wrong time of the year to see Blue-crowned parakeets …

I cross-referenced the two lists automagically using a short perl script and then manually corrected the dozen or so species from Ardnamurchan that disagreed between BTO and EURING systems 12.

Inevitably this manual bodge will break things in the future …

A picture is worth a thousand words

One of the problems with the BTO Bird Atlas maps is that the Ardnamurchan peninsula is rather difficult to see. I therefore created a series of small 3×2 gridded icons representing the six NM-prefixed squares that cover the peninsula. I used one icon for the winter distribution and one for the breeding distribution (with probability indicated by different sized ‘blobs’, just as they are on the BTO Bird Atlas maps). For example:

This icon    represents a species that is recorded in all but NM57 in winter.

This icon    indicates a species which possibly breeds in NM46, probably breeds in NM66 and NM67 and that breeding has been confirmed in NM56 and NM57.

There are ~132 different distributions of birds in the winter and breeding seasons. Rather than draw any of the icons by hand I used ImageMagick to create them automagically, called from a perl script that read the underlying data directly from the distributions.csv file.

I also added a notes column, but this has yet to be populated.

The finished list of Ardnamurchan birds in the most recent BTO census is linked from the menu above, or directly from here (and is also available in PDF format). It will be updated as and when new BTO census data is released.


Notes

  1. It should be noted that for security reasons the breeding distribution of some rare birds is deliberately listed (by the BTO) at lower resolution.
  2. There’s a second minor problem with the BTO Bird Atlas maps. They are displayed via a server which separates the delivery of the map from the menus that control the data displayed or its appearance. This means I could either link directly to the maps (and have no menus) or to link to the default map for a species and subsequently select the desired map (which has to be done interactively).¬†The default map is the most recent breeding distribution, so this is linked from the ‘summer’ icons. Until I find a way to access the winter distributions¬†and menus I’ve left the ‘winter’ icons linked directly to the relevant map alone.
  3. The Blue-crowned Parakeet (Thectocercus acuticaudatus) is a small green South American parrot with a blue head. They inhabit Neotropical savanna-like habitats, woodland and forest margins from eastern Columbia to northern Argentina. Not Ardnamurchan ūüėČ

Blue-crowned Parakeet