Sunday, 5 July 2020

Quarantine entry #106 - July 5


Obligatory disclaimer: real life sucks, but at least I will be getting a haircut today. Yay! What shall we talk about?

According to the initial plan – about the barn owls, but the problem is that they’re owls – and owls may look different from each other, but the basic design is the same, the family traits are there and in the open.

…This is part of the reason as to why classifying owls upon the greater animal tree of life is tricky – yes, they are birds, but what are their closest relatives? Right now, they are part of the Afroavian clade, whatever that means, but to a layperson? One owl is as good as another, and-

-And they are not entirely wrong either, for while a barn owl may be only distant related to the short-horned, (or the long-horned – North America has both of those species), owl, but beyond that, physically, they are similar.

…Yes, physical similarity isn’t a very reliable means of establishing relationships, but it does work, plus we’re talking about the ecological aspect here and now instead: all owls, from the great snowy owl, (a relative of the eagle-owl and the great horned owl that we’ve discussed earlier), to the tiny elf owl, live the same lifestyle: they are birds of prey that can hunt at night. They can hunt during the day, in fact, the burrowing owl is actually a diurnal bird, but they hunt during the night, when the hawks, eagles and falcons – as well as most other birds – are asleep and cannot compete with them, nor escape from them as readily as they can during the day.

The other birds are aware of that, sort of, as they mob the owls during the day and otherwise harass them. Songbirds are one thing, but if we are talking about the bigger corvids – jays, crows, and ravens – then an owl may be in some serious trouble, as those bird species are both big and social, unlike the owls, who are more of loners instead.

Pause. Again, the punchline here is that birds of prey, including owls, aren’t social, but loners; the Harris’ hawk is the only exception, though it can be pointed out that some of them are known to perch in large groups, for example – the previously-mentioned long-horned owls. They are known to perch in groups of almost a dozen – that is a lot for solitary nocturnal hunters. But…

…But perching alone does not make social bonds – the long-horned owls may tolerate each other, they are actually not very confrontational, by owls’ standards especially, but otherwise, they don’t hunt together, as wolves, or even Harris’ hawks do – each bird usually has its’ own hunting spot and it doesn’t tolerate any rivals there. The size of this hunting spot/territory may vary, but it is there, period. Anything else?

…This brings us back to the issue of owls’ physical similarity to each other, period. A long-horned owl may be much closer related to a short-horned owl than to a barn owl, but in many ways the three birds are built along similar lines – they are all owls, after all. If you add other owls, the family similarity will not be any less noticeable. Why?

Because all owls are predators. They are nighttime predators. They are predators, primarily, not of other birds, but of other vertebrates…or in case of smaller species, such as the screech owl or the saw-whet, of large invertebrates instead. Unlike most of the birds, the owl prey is active at night as well – we are talking mice here, voles, rabbits & hares, etc. – and so the owls need to be extra stealthy to catch them. There usually not too much variety either, aside from the size… saving for the fish owls and the fishing owls. No, these are not synonyms: fish owls usually have tufts of hair on their heads, look rather like eagle owls, and belong to one genus, while the fishing owls belong to another, and have no tufts. All of those owl species, (there are about seven of them, I think), hunt fish, just as the osprey does, and since fish can’t hear sounds that come from air, these owls are as noisy as an osprey is.

This brings us back to co-existence: these owls hunt the same prey as the osprey does, just as the rest of the owls hunt prey items that are similar to those of other carnivorous birds, (such as small falcons). Only… not, because while hawks, kites, and especially falcons are bird specialists, owls hunt prey items from mammals, reptiles, amphibians and so on, which allows them to co-exist with their counterparts during the day…mostly. There are exceptions – for example, the eagle owls and black kites, as we have discussed earlier – but these exceptions only underline the main rule…

Well, this is it for now. See you all soon!

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