Phenology Report, November 22 2022
The seasons march on, as they tend to do! This week, John starts with a brief botanical note. In Grand Rapids, the last holdouts of deciduous trees and shrubs have finally dropped their leaves; lilacs, white poplars, and even buckthorn shrubs are bare. (In the Twin Cities, the buckthorn is still green.)
John decided to focus part of the report today on a bird that's captured my interest this year: the Northern Shrike! These amazing birds are back in the area: reports are popping up on the KAXE/KBXE Season Watch page! Here's what he had to say:
There's an odd bird that shows up here in the Northland every winter. Not odd in the sense that it has extraordinary plumage or flies in an unusual fashion; rather, it is a songbird that eats flesh. It actually hunts down, attacks, and kills mice, voles, insects, and other songbirds. All other birds with such eating habits are relegated to the Raptors group, but not the Northern Shrike! It maintains membership with the Passerines. Passerines, roughly defined, are perching birds that possess vocal organs and are capable of songs. They also have a particular arrangement of toes (three forward and one backward) and muscles that tighten and secure the perch when they sleep. The Shrike meets these requirements, but its habits of preying on its fellow songbirds make it a bit of a pariah within the order.
The Northern Shrike is a robin-sized bird with ash-grey plumage on the body and black wings and tail. The tail has white feathers along the outer edges, and there is a white patch evident on the wings. When the bird is in flight, the head is neatly bisected by a black slash of feathers starting from the base of the beak. The beak is large and black, and it has a prominent hook at the tip. To a casual observer, it might be mistaken for the more commonly seen Grey Jay, but the presence of the black colors on the wing tail should be definitive: the Grey Jay only has black on its head.
Our Northern Shrike has many names across its range. Butcherbird, Winter Butcherbird, Northern Butcherbird, Nine Killer: all stem from its scientific name, Lanius excubitor. [Editor's note: some sources, e.g., the Cornell Lab of Ornithology, refer to this species as Lanius borealis] 'Lanius' is for 'butcher,' and 'excubitor' is for 'sentinel': a perfect description of the bird's habits. It often perches on the highest vantage in the area, and when it has captured its prey, it will impale it upon a thorn or barb (sometimes hanging it from a crotch in a shrub), somewhat like the butcher who advertises their goods in the window.
Speculation has it that the shrike hangs its meals because its feet lack the strength required to hold the victim while the bird tears away the flesh. Stories of eyewitnesses to shrike attacks reinforce this idea: rather than strike with the feet, as a hawk or owl might, the shrike uses its beak to subdue its adversaries. One such observation involves a field mouse dragged to the surface of the snow, then released so that the shrike might find a better purchase on it. The mouse immediately attacked and sprang at the shrike, driving it back several feet. The shrike was able to parry the attacks using its beak to deflect the advances, hoping it had gained enough space to beat a retreat. The mouse turned and ran in two quick bounds. The shrike was on the mouse and, grabbing it by the neck, shook it vigorously from side to side the way a dog might shake a rat. Pausing, the shrike bit the mouse along the neck and killed it.
The hook at the end of the shrike's beak is designed to facilitate this clipping of the neck.
John mentions that he's heard reports of a local Northern Shrike attacking a downy woodpecker and killing it in the same fashion: that hooked beak works as well on birds as on mammals! If you're lucky enough to have one in your area, take time to get out and observe it. They're definitely one of the wonders of our region. [I've attached an absurd little video on shrikes below, but it is graphic! They call it the 'butcher bird' for a reason.]
The Northern Shrike isn't the only awesome bird in the area: John saw Pine Grosbeaks and Evening Grosbeaks! Members of the Season Watch Facebook Page have also posted their sightings, so the species have returned in good numbers. Pine Grosbeaks have prominent red coloring, while Evening Grosbeaks are vibrantly yellow, black, and white. Both species have the large beak that gives grosbeaks their name! Last year, John had a flock that hung around for several consecutive weeks, and he was thrilled! Whether their increased abundance is due to a recovering population or poor conditions in their northern range, John's happy to welcome them to the area. (Evening Grosbeaks used to be common, but have declined in numbers.)
This week, John watched a pair of ravens engaged in a bonding flight. They were flying together, mimicking each other's motions and movements: a third raven, likely their offspring, sat and watched. This bonding flight is common for a bonded or breeding pair. They'll stay together throughout the winter, defending a territory and searching for food. Juveniles will move on and join a larger flock of unmated birds: these flocks forage over a large area and will all settle in an area at once, wiping it clean of resources before moving on.
Thus, the deconstruction of a roadkilled deer will be very different, depending on who finds it: a mated pair will be very quiet about it, breaking it up into pieces and caching as much of the meat as possible to enjoy throughout the winter. If, however, one of the large flocks of unmated birds finds the carcass, they'll overpower the mated pair and strip it clean quite rapidly.
It's a great time of year to observe raven behavior. Not only are they easy to observe (they contrast so nicely with the white snow!), but they're often easily located along roadsides. You can distinguish ravens from crows by looking at their tails: ravens have a diamond-shaped tails, where the middle feathers are longer than the outer feathers. Crows' tails are squared off. Crows will often attack ravens, which gives you an excellent chance to compare them side-by-side! This is a particularly good opportunity to notice the size difference between the two species: ravens are almost twice as big as crows. Want to learn more about ravens? John recommends the book The Mind of the Raven by Bernd Heinrich.
Aside from the ravens, grosbeaks, and shrikes, John's had his eyes on juncos and Bald Eagles. The local Bald Eagles are paired up, but not on the nest. They only occupy the nest while actively incubating eggs or raising young, which occurs in spring and summer.
That does it for this week! Phenology in the late fall and winter is pretty animal-centric, so get out there, find some animal tracks, admire some birds, and enjoy the season.
For more phenology, subscribe to our Season Watch Newsletter!
Funding for this project was provided by the Minnesota Environment and Natural Resources Trust Fund as recommended by the Legislative-Citizen Commission on Minnesota Resources (LCCMR).