Mme. Owl stopped by the nest box at 6:04 AM CST to do a little nest site prep. That consists, as usual, of kicking around the bedding material to make a depression for the eggs she’ll eventually lay. Another means to the same end, not seen here, is for the female to push the bedding material around using her breast like the blade of a bulldozer. That behavior, however, may be reserved for looser material than that currently present in the nest box.
December 29, 2012, 6:04 AM CST
40.6 MB MPEG-4 movie.
The material in the nest box, BTW, is what was left after last season's breeding. I haven't made any effort to replace it. One reason is laziness; egg laying shouldn't begin in these parts until March, and the last time I went looking to buy wood shavings (as used in hamster cages, for instance) all I could find was something resembling cat litter. The other reason is that I need to move the nest box to a living tree before nesting commences (a project I admit to putting off due to the fact that it's going to be a major pain in the ass), and leaving the old bedding material, rich with familiar owlet smells, in the box should help reassure the adult owls that this is the same nest they've trusted for who-knows-how-long, just miraculously relocated. I have no evidence that that will be considered significant by the owls, but it seems like a reasonable possibility with no downside.
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owls allegedly have no sense of smell, but they probably have twelve other senses we've never heard of that can decode wood chips.
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ReplyDeleteYes, I've encountered that assertion in good books. On the other hand, my friend the raptor rehabber maintains that, based on her decades of bird-in-hand experience, avian olfactory capabilities overall are radically underestimated. And that owls, specifically, (or at least all the species that pass through these parts) have a perfectly good sense of smell. I'll have to ask for details the next time we talk, but even if we assume they can't aspire to the olfactory prowess of vultures or canines, if they can just manage something like humans' pathetic sense of smell, they'll know whether the nest box smells familiar or not.
ReplyDeletefrom your firsthand knowledge of borrowing owlets, etc. - how significant is the smell in there? Must be notable.
ReplyDeleteDo you see them sticking their heads out in the PM when they are in the box during the day? I've moved my box but haven't noticed any activity.... No owlcam in my box though just relying on an afternoon sighting.
ReplyDeleteKeep up the posts and video - I'm loving it.
During nesting, I definitely see the female stick her head out of the box in the afternoons. Three conditions seem to encourage that: warmer weather, a herd of rambunctious owlets below her, and boredom. The warmer weather is important for two reasons: she can't leave the owlets for long until they are old enough to maintain their own body temperatures (in whatever weather is present; warm weather allows her more time away from them), which makes a quick sit in the entryway her only option much of the time, or the weather gets hot enough, that her only access to cooler, fresher air is from the entryway. The owlets begin being rambunctious at around two weeks of age and then get better at it by the day, until I'm sure Mme. Owl is just glad of some time away when they aren't flapping their wings in her face, etc. Of course, she generally leaves the nest entirely when the owlets are three weeks old, partly because it's getting cramped in there, then there's the rambunctiousness, the smell, her need to be a free owl again, after spending almost all of seven weeks stuck in a box (or natural nesting cavity, etc.), and the fact that it encourages the owlets to begin thinking about leaving (or, at least, thinking about how all good things come from outside). Finally, there's boredom. I can't prove it's there, but, to me, it seems obvious that a creature normally spends all its nights carefully observing as much as possible of what goes on in its territory, and skillfully capturing any of that that happens to be the right size for eating, must find those seven weeks in a box something akin to sensory deprivation. So, sticking her head out the entryway to watch (and listen to) the world going by, would be a welcome relief from staring at the same six walls all day and night.
ReplyDeleteRegarding burrowing owls, I've met only a few, and only while they were in rehab for various injuries. Great birds. Wish my backyard came with its own prairie dog colony, so I could get some burrowing owls here. (And the prairie dogs would great, too.) Anyway, based on my very limited experience with burrowing owls, I have no idea what the smell might be like in those burrows, but I would note two things: the soil in which those burrows are dug is very much alive and healthy because of all the biological activity those burrows support/enable, which would suggest to me that any animal waste, or sources of other unpleasant odors, would be continuously processed into rich soil by various macroscopic creatures like worms and insects, and most assuredly by uncountable microscopic species in the all-surrounding rhizosphere. etc. The second point I'd note is that the burrowing owls, like the prairie dogs, evolved for life in those tunnels, so I would be surprised if, whatever the odors down there, the owls, dogs, and other routine inhabitants aren't completely accustomed to them (and their genetics may have made even accustomization unnecessary), therefore, to them, I would guess, it either smells like nothing, or like home. Burrowing owls aren't always found with prairie dogs (though I suspect that, given the option--which would once have been extremely common--to occupy an existing tunnel network, rather than create their own, the owls would opt to use existing tunnels, and take advantage of some symbioses with the dogs, like a common predator warning network), but all of the points above still apply.
ReplyDeleteThanks for the insightful reply Chris. What's your experience with owl peaking in the 'off season'? I'm assuming warm afternoons with direct sun on the box would encourage this behavior. I've heard that owls really like being warm and hardly ever roost in spots where they would be cold.
ReplyDeletewow, even when I don't communicate well and my dumb jokes tank, I learn a ton of stuff! Thanks for the great answer on burrowing ones! I was actually referring to your shady practice of, as you put it, BORROWING owlets for photo shoots - at which point you must get a blast of fully ripe nestbox air!
ReplyDeleteOh, yeah, borrowing owlets. Yes, the bedding material does get a bit ripe, especially toward the end. Fortunately, the box was designed to let the bedding dry, to some extent, from its lower, as well as its upper surface. That helps, but I'm not sure that it is representative of natural nesting cavities - those could, conceivably, have the heartwood of the tree to absorb whatever passed through the naturally occurring bedding (whatever squirrels, or other bird species had previously deposited in the cavity). Also, there could be a whole nesting-bird-oriented flora and fauna living in that heartwood and decomposing bedding. Either, or both, factors might lead to a more pristine nest. Never having had the opportunity to examine natural screech owl nest cavities, I'd have to defer on this point to someone like Fred Gehlbach, who has. Unfortunately, I don't remember him discussing this issue in his screech owl book.
ReplyDeleteOther points: Mother screech owls eat owlet feces in order to keep the nest as clean as they can. Aiding that, after a certain age (one week, two?), the owlets begin moving to the corners of the nest box to defecate (and, presumably, to urinate), so staying clean has come to have some meaning to the owlets, possibly instinct, possibly just the logical first step in a lifetime of careful feather maintenance.
This raises a more general issue that I've been pondering for years: Are artificial nest boxes good emulations of natural nest cavities? The former can easily be superior in drainage and predator protection (if designed right), but are they as well insulated, do they support my conjectured micro-environment of flora and fauna that might take care of some nest cleanup duties, etc.? We know artificial nest boxes can work (we also know that badly designed ones can be death traps - drowning whole nests of owlets, among other things), but are even the good artificial nest boxes all that they should be? I plan on exploring that issue in future nest box designs, by insulating the walls, possibly doing something clever with the floor/bedding arrangement, and whatever else I can think of.
Re: mother screech owls? Stranger things happen at sea, I guess. I wonder who first noticed that they do that, and how. We humans sure don't like minding our own business, do we ;)
ReplyDeleteThanks for the great answer, Chris, and a good new year to you and to readers of this blog!