The Daily Bucket is a nature refuge. We amicably discuss animals, weather, climate, soil, plants, waters and note life’s patterns.
We invite you to note what you are seeing around you in your own part of the world, and to share your observations in the comments below.
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August 9, 2019
Pacific Northwest
Baby bird season is winding down hereabouts, which is why the activity of the Red-breasted nuthatches stands out right now. We’ve been seeing many more than usual visiting the feeder, and hearing nuthatch beeps from the trees more often. Looking at phenology information (that and other data from Birds of North America birdsna.org/..., a site that has copious links to research studies) this is either late or what we’re seeing is a plethora of youngsters now independent who are remaining in the nesting area beginning winter behavior.
Nuthatches are nonmigratory in Washington. The Red-breasted (Sitta canadensis) is the only nuthatch west of the Cascade mountain range; two other species are found to the east (White-breasted and Pygmy nuthatches).
Their feeding behavior shifts completely after the breeding season. During nesting, which includes 2 weeks of incubation, 3 weeks feeding nestlings and for at least part of the 2 weeks post-fledgling parental care, nuthatches feed on insects. Quantitatively, mainly beetles, caterpillars, spiders and ants, with lesser amounts of other insects.
Once out of breeding season, nuthatches shift to seeds as about half their diet. As conifer forest dwellers they’ll go for the seeds of the trees around them. In my neighborhood that’s mainly Douglas fir, Grand fir, Redcedar, Western Hemlock, Sitka Spruce.
They readily visit both our seed and suet feeders year round. The seeds we supply are Black oil sunflower seeds. Unlike the finches, nuthatches are strictly grab-n-go feeders. They never perch and eat there. The nuthatches select a seed and fly away to either eat elsewhere or to cache it for winter.
In winter it’s rare to see more than one nuthatch on the feeder. Right now I’m frequently seeing several at a time, sometimes perched up on the hanger surveying the situation. Most of the nuthatches are very light below, which is the coloration of females and juvs/immatures. This suggests the youngsters are learning how to do winter feeding, and perhaps even caching.
There are many insect feeding birds, seed feeders and cavity nesters amongst the birds out there. But nuthatches are unique in one remarkable way:
The most unique aspect of nests is the sticky conifer resin applied by parents to entrance of cavity (Tyler 1948b, Kilham Kilham 1972a, Kilham 1973c, Kilham 1975b, Rand 1972). Males and females bring resin globules in tips of bills or on small piece of bark that functions as applicator throughout incubation and nestling periods (Tyler 1948b, CKG and TEM).
In general, parents and young are well adapted to dealing with resin at nest (see also Fledgling stage, below). Incubating females are particularly adept at diving into nest cavity at high speeds without soiling their feathers, and both parents dive into nest with great precision to feed nestlings (Kilham Kilham 1972a, Kilham 1973c, Kilham 1975b, CKG). However, resin occasionally becomes hazard to parents; Kilham (Kilham 1972a) found a dead female stuck to resin at 1 nest, but this appears to be an uncommon event.
Most observers (e.g., Tyler 1948b, Kilham Kilham 1972a, Kilham 1973c, Kilham 1975b) have hypothesized that the sticky resin serves as barrier to prevent predators and competitors from entering nest cavity, although others have argued that applying resin may simply be nonadaptive behavior deeply rooted in nuthatch phylogeny (Rand 1972, Pasquet 1998).
When conifer resin was experimentally added to entrance of nest boxes in central Arizona, House Wrens nested only in boxes without resin. Similarly, when resin was added to nest boxes that had been baited with food, red squirrels and deer mice (Peromyscus spp.) showed a significantly greater aversion to boxes with resin, suggesting that resin can reduce both competitive and predatory interactions (CKG and TEM unpubl.).
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Overcast this morning in the PNW islands, looks like sun may burn through soon. Daytime temps have been running into the mid-upper 60s these past few days, nighttime still in the 50s.
What’s the nature news in your neighborhood?
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