High mortality among juvenile barn owls is causing concern among the Island birding community. Over the years much effort has been expended upon re-establishing the formerly widespread, beloved owls with quixotic clown faces. On the Vineyard in more rural times the many barns, haylofts, and farm outbuildings provided not only nesting sites but also prey.
So far, post-mortem examinations have shown that the deceased Vineyard animals died without food in their stomachs, seemingly ruling out rodenticide or disease as a cause of death. While there are several possible explanations, including the irruption of snowy owls into our lower latitudes, these will be dealt with at greater length by our knowledgeable Island bird experts.
My interest in the barn owl deaths is on behalf of many gardeners who have been plagued to exasperation by rampant numbers of voles in their gardens. Preferable by far is rodent control by natural means, in which birds of prey, including owls of all species, play a paramount role.
Preferable by far is rodent control by natural means, in which birds of prey, including owls of all species, play a paramount role. Suzan Bellincampi of Felix Neck directed my attention to an article titled “Poisons Used to Kill Rodents Have Safer Alternatives” by Ted Williams in the January-February 2013 issue of
Audubon Magazine (audubonmagazine.org) detailing the pervasive ecosystem effects of, and potential harm posed by, the use of second-generation rodenticides.
At this point I must admit to my use of rodent bait packs in my efforts to limit rodent activity here at our place, where the number of linear feet of stonewall, retaining the slope of the property, provides superb cover for several different rodent species.
Since I keep chickens, I never previously gave rodent control a whole lot of thought. I was focused on eliminating vermin, not on the long-range effects on my local ecosystem. But we are also rich here in owls, alas — no coincidence when there is good habitat and a food-source for rodents — so, am I poisoning them?
It was thought the target rodents were becoming resistant to warfarin, the first-generation product. “Both first- and second-generation rodenticides prevent blood from clotting by inhibiting vitamin K, though the second-generation products build to higher concentrations in rodents and are therefore more lethal to anything that eats them.”
Furthermore, according to the Audubon article, in 2011 Maureen Murray, a researcher, “found rodenticides in 86 percent of the raptor livers she examined, and all but one contained brodifacoum, especially deadly to birds…. In California, the only state other than New York that has looked carefully, rodenticides showed up in 79 percent of fishers (one fisher even transferred poisons to her kit via her milk), 78 percent of mountain lions, 84 percent of San Joaquin kit foxes, and, in San Diego County, 92 percent of raptors.”
The rodenticides will eventually lose their effectiveness as the many generations that rats, mice, voles, and chipmunks are capable of speedily producing become resistant. Their predators, such as our owls and, yes, our chicken-killing hawks, must remain viable as agents of natural control. If we kill them off we will never maintain any degree of viable natural rodent control.
In the Garden
Snapshot of January since New Year’s: snow, dramatic rainfall in multiples of inches, spikes of high and low temperatures, lovely little January thaw. The time of sunrise finally peaked after the New Year at 7:16 am and is now regressing, by a minute every three days or so, until currently it is 7:09 am. In contrast, the sunset has been getting later since a few days before the solstice and is currently at 4:50 pm.
Buds are visibly swelling. The witch hazels began to bloom in the week of January 12. The tips of narcissi bulbs are showing; but before spring arrives there is likely to be much more wintry weather in store for us. Let’s not get too excited.
During spells of nice weather, get outdoors and have a look around. Processes of nature are underway, even if we prefer to remain inside ruminating upon seed catalogues. Dogwood — the native one, Cornus florida — displays prominent buds swelling daily, as do other flowering shrubs and trees, such as swamp maple (Acer rubrum), corylopsis, and honeysuckles.
However, do not be tempted to commence routine pruning associated with spring clean-up. Climate change and possible average warming are not likely to proceed in a smoothly upward-sloping trajectory, but rather in spikes and troughs, fits and starts. The term “climate change” itself connotes instability, in patterns with which we are familiar, or in changes that are unexpected.
Cold snaps or warming spells can be equally stressful to plants once they have settled into their winter routine. The old wood and dead herbaceous matter on sub-shrubs and perennials confers some protection against extreme fluctuations in weather conditions, such as freeze/thaw cycles. Removing it prematurely also removes that protective function. (Storm or ice breakage may be tidied up any time it is noticed.)
Blueberry twigs are reddening and the colorful plants, of great interest in the winter landscape, may be pruned now. Look to remove old, gnarled wood and to promote vigorous, reddish growth loaded with fat flower buds. Dried blood is one of the best fertilizers for blueberries. The old wood of Vaccinium corymbosum is hard and dense: good, clean cuts are best made with freshly sharpened pruning tools.
Homegrown met Sunday. Among topics discussed were soil testing and onion/leek seeding — do both now — and the establishment of a local seed library. Awareness of the importance of the native plant biome and an enduring food-crop germplasm collection is reaching new levels. A seed library is an interesting project likely to become a reality on the Island in the near future, with the possibility of a seed-school workshop being conducted in spring. The Homegrown group also looks forward to its establishing a Homegrown members’ forum (blog). Coming right up is the deadline for the Homegrown group potato/onion order, February 6.