Okay, here’s a slightly deceptive Guinness Book of World Records award for the Shortest Bird Migration:
In stark contrast to the thousands of kilometres flown by certain migrating birds, such as the Arctic tern (Sterna paradisaea), the world’s shortest migration is that of North America’s blue grouse (Dendragapus obscurus). During the winter, it inhabits mountainous pine forests, then when nesting time begins in springtime it descends a mere 300 m to deciduous woodlands in order to feed upon the early crop of seeds and fresh leaves.
This bird is commonly called the dusky grouse, and looks like this (male above, female below):
Well, 300 vertical meters is longer than that horizontally, but if you count this as a real migration, then it’s still probably the shortest one known. Curiously, the Cornell bird site is less informative than Wikipedia here on the “migration”:
Their breeding habitat is the edges of conifer and mixed forests in mountainous regions of western North America, from southeasternAlaska and Yukon south to New Mexico. Their range is closely associated with that of various conifers. Their nest is a scrape on the ground concealed under a shrub or log.
They are permanent residents but move short distances by foot and short flights to denser forest areas in winter, with the odd habit of moving to higher altitudes in winter.
These birds forage on the ground, or in trees in winter. In winter, they mainly eat fir and douglas-fir needles, occasionally also hemlockand pine needles; in summer, other green plants (Pteridium, Salix), berries (Gaultheria, Mahonia, Rubus, Vaccinium), and insects(particularly ants, beetles, grasshoppers) are more important. Chicks are almost entirely dependent on insect food for their first ten days.
Now we have many readers who are birders. Is Guinness right in counting this short movement as a “migration”?
I’m not particularly a birder, but if they move from one habitat to another on a seasonal basis, why shouldn’t we call that a migration?
I think it’s a human semantic issue rather than anything with meaning for the life-ways of the birds concerned! One of the longest migrations, incidentally, is by Godwits which fly in September from Alaska to New Zealand, non-stop. They arrive on our beaches and virtually collapse, taking some hours even to be able to fold their wings. The return is easier, taking about three months from March and staged via north Australia, Korea and Kamchatka.
Those poor godwits! Does anybody help them when they arrive in NZ?
Not really, though some of the places they land, such as the Manawatu river mouth, are protected wetlands, so they’re relatively safer there.
Elevational migrations are common among birds in the world’s montane regions. Many are likely to be this short, but many are also longer.
Yet another example of altitude standing in for latitude…
I live in the foothills of the Manzano mountains in NM. We get juncos and pine siskins by the dozens at our feeders in the winter. They go up to the mountaintops for the summer. I have seen them up there when I’ve been hiking.
It’s further than three hundred meters, though.
L
The Princeton Encyclopedia of Birds defines it as:
Migration
usually the behavior in which birds fly (migrate) from one part of the world to another at different times of year. There is also local migration and altitudinal migration where birds move, e.g. on a mountainside, from one height to another.
Other than birds, quite a few other animals change elevation by season.
Um … ouch?
I am not a birder, can they digest that? Less silica content than grasses I am sure, but reasonably hard coated and not very voluminous (so less content unless the coat is digestible).
The grass silica defense is more problematic for teeth or beak than stomach as I understand it, but it is the one that comes to mind.
There is not much else alive at that elevation in the dead of winter…
It doesn’t need to be alive to be edible. He says, tucking into a bowl of cereal, covered in milk. Is milk alive?
The Red Grouse locally – the ones who don’t consider 12th August to be so “Glorious” – live on leaves of heather, which are not exactly succulent either. They have a fairly stocky body, so room to ferment a lot of plant matter. A worthwhile question might be – do they have much in the way of gastroliths in the crop, for grinding up their food before going into the stomach?
I’m still trying to figure out why, in one wildcat well, we got hundreds of metres parrent vertical thickness of mud (clay, <1/256mm) with highly polished quartz and lithic pebbles up to 5mm diameter, when several hundreds of km from a sediment source. We tossed the question around for days while killing the well with everything up to a stake in the heart and garlic in the mouth, but the leading contenders were either a nearby mud volcano that managed to hide from 3 ODP seismic surveys and 2 proprietory surveys, or lots and lot and lots of gastroliths. Question filed as a "someone else's probem" once we got the well dead enough to log and then cement.
Noah’s flood, obviously.
Sub
I can’t really say, technically, but I’d give the blue grouse the honor, if that’s what it is, of being a migratory species, simply because it looks very classy with that pink shoulder patch.
I’ve tracked lizards that move almost as far between summer and fall.
There’s a term in the humanities for when populations move to higher altitudes for a season or so, to exploit temporary resources : “transhumance”. Covers such circumstances without the dramatic baggage of “migration”.
I was surprised a while ago to discover that some migratory birds resorb their sex organs and digestive organs to provide energy for migrations over the Sahara. Pretty dramatic stuff.
The dust bunnies in my apartment migrate seasonally from under my dining table to the corner of my bedroom, a distance of about 30 feet, depending on whether the HVAC is in heating or cooling mode.
That’s a good point if we’re talking about animals in general and not just birds. In that case, if you put a flea collar on your dog, his fleas might migrate a couple of feet back to his tail.
Dust bunnies are animals, right? Hmm… maybe I’d better look that up.
The Canadian geese who live at the golf course near my folk’s house fly around in circles for a while before returning to the golf course.
Typical Canadians. To polite to defecate where people walk. 😉
No, it’s not the shortest migration. As readers have already pointed out, there are a variety of movements in birds. These movements can be usefully categorized in many ways. The usual migratory/non-migratory categories can be useful, but generally refer to situations, common in the north temperate zone, where some species depart the breeding grounds completely and travel long distances to the wintering ground (e.g. swallows), while others remain in the same general vicinity (e.g. crows). By this categorization, the blue grouse is non-migratory. But there are other ways of categorizing movements. The grouse is making a seasonal altitudinal change– many birds (and mammals) do this– which is referred to as altitudinal migration, but they remain in the same general geographic area. Here’s what my colleague Johannes Foufopoulos and I wrote in a paper on Aegean birds:
Many tropical birds are known to move short distances in season to take advantage of fruiting, insect hatches, etc. Some of these may be on a regular basis and could be regarded as ‘migrations’. Many of these movements are little known and little studied but it is clearly premature to give the accolade to the grouse.