My best friend at junior school lived in a house with quite a big garden and together with his older brother, he used to simultaneously feed and torment a Robin. They had a knitted robin which they would mount on an old camera tripod set up in the middle of the lawn, close to a tray of mealworms. The Robin which had secured the territory would totally savage its apparent rival, usually knocking it off its perch and to the ground, where the assault would sometimes continue. Eventually, the knitted robin fell to pieces, the supply of mealworms was exhausted and the experiment ceased. Several experimental scientists-to-be were involved in these somewhat informal procedures, though I fear that our laboratory notebooks would not have withstood scrutiny and that the proposed experiments would have failed to secure ethical approval. Anyway, we’ll come back to Robin-based experiments later on.
Robins can absolutely be relied upon to perch nicely. The old signpost used to stand at the bottom of Geilston Lane, just above the high water mark at Cardross. The short walk from the rail station and sawmill to Murrays passes through at least half-a-dozen Robin territories; it’s very unusual to take this path without seeing several Robins, strung-out like shirt buttons along the path. I’ve never been aware of strife along the route even though territories are defended throughout the year, according to my RSPB book. I’ve rarely seen two together, but I do have this shot from beside the Kelvin.
A Robin has decided to hold a territory behind our house in Glasgow; the singing starts in the small hours and continues into the dusk. I’ve been recording it – here’s the extended remix, just over one hour in length. I think there are two birds competing at one stage, and you’ll hear some of our other regular visitors.
Robins are sedentary in some regions and migratory in others. I thought I knew that UK populations were boosted in winter by Robins from Central Europe but I struggled to find evidence for this in the primary literature, despite working hard with keywords and citation searches. I did find a piece in Country Living, of all places, from 2019. A “nanotagged” Robin flew in four hours from Heligoland to Felixstowe via Amsterdam under cover of darkness. Chris Hewson of the BTO had apparently spoken to The Times about these findings and I wrote to him, hoping that he would identify the relevant research publication. Alas, he didn’t. I did find some interesting BTO webpages on tracking methods.
The tag used on the Robin weighed about 0.3 g, ca. 1.5% of the bodyweight of a 20 g Robin. That’s about the same relative loading as me running back home from Screwfix in Possil Park with a large box of Polyfilla, something I have been known to do, but not for hours, and not over water in the dark. I do sometimes wonder about the ethical calculations carried out in advance of tagging experiments. Still, as batteries get smaller and better, so do the tags. I was also intrigued by Country Living‘s use of the nano- prefix. Anyone with a science background knows that nano- is Greek for “Give me a large grant, now…”; more seriously, 0.3 g is more milli- than nano- (only a factor of 106 out, then), but it would appear that devices are getting smaller and less significantly burdensome, particularly for the smaller birds. I’m glad the little chap landed in Felixstowe, rather than, say, Frinton-on-Sea; there are some nice people in Felixstowe (hello Ricard, if you’re reading), whereas the Brexiters of Frinton would have probably kebabed him.
I found an interesting piece about Robin migration which did not use tagging, not open access, alas, but I will give the reference (Catry et al., Oecologia, 2016, 182, 985–994). Because feathers, once fully developed, are metabolically inert, they reflect the environment in which they were grown. There seem to be consistent differences in the relative amounts of deuterium, hydrogen’s heavy stable isotope, within the feather protein (keratin) between birds from different locations. The team sampled feathers from a wide range of European locations and mapped them by isotope ratio, determined by mass spectrometry. This technique which effectively “weighs” molecular species to an astonishing level of precision, allows very small variations in hydrogen/deuterium ratios to be detected and quantified. Feather samples taken from migrant birds on the Iberian peninsula, a destination site for many birds from northern Europe were also examined. These isotope ratios could be used not only to assign the origins of Robins wintering on the peninsula, but also to reveal how the birds were organising themselves with respect to habitats and food sources. This technique sounds less invasive than tagging but the environment or habitat mapping is a lot of work! Of local interest, the mass spectrometry was carried out at NERC’s facility in East Kilbride which falls under Glasgow University’s umbrella, but has nothing attractive to offer in terms of a web presence, which is a pity.
The other research findings I wish to report sound like a bit of a torment (Lind et al., Behav. Ecol. Sociobiol., 1999, 46, 65-70, again, not an open access publication, alas). Robins were fed to different fuel loadings (this means their masses divided by their wing surface areas) and had a model Merlin launched at them to see if they could vary their angle of ascent in response to the approach trajectory of the predator, and if their weight had an effect on that angle. The answers seem to be “no” and “yes”, with the more fuelled-up Robins getting off less steeply. I thought the following text was quite interesting: “Robins are not forced to cross any extreme barriers, and they do not migrate as far. They may therefore travel with smaller fuel loads and thus be better able than, for example tropical migrants, to give priority to safety during migration. When the Robins arrive at the wintering area, they do in fact choose territories mainly for protection, and not for good feeding opportunities.”
The Robins I meet at my fishery definitely do not see me as a potential predator. I throw and catapult maggots into the pond, and I drop a good many so they’ll be crawling all around me after a while, and the Robins come right to my feet for them, taking great bundles away. Once they’ve tidied me up, it’s straight into the bait tray for the grubs or whatever else I have there. I haven’t managed to photograph this action – they’re a bit too close to me to be relaxed in front of the camera.
On one summer visit, I ended up feeding a shoal of big Ide in front of me and young Robins and Blackbirds (two of each) behind me, and I went through quite a bit of bait that day.
If anyone is interested, here’s a video of two of our most public-facing match anglers (Andy May and Jamie Hughes) catching Ide at a commercial fishery – the action starts around 7:45. Fish are caught during this video so please don’t watch if that’s likely to upset you.
Finally, the Christmas card department – who can resist Robins and snow. Not me. I’ve one from Frankfield Loch near Stepps and two images of the locals in Kelvingrove Park (including a “digital print”). Backwoodsman will post again on Saturday 4th March, with any luck.