A Northwoods Almanac for 10/28 – 11/10/22 by John Bates
2022 State of the Birds
The U.S. Committee of the North American Bird Conservation Initiative recently released their 2022 State of the Birds report, and their findings included this good news: Waterbirds and ducks in the U.S. have increased by 18% and 34%, respectively since 1970. Their increase is attributed to investments in wetland conservation, including the Federal Duck Stamp program and contributions from excise taxes and license sales to hunters.
Now the bad news: More than half of U.S. bird species are declining.
Within that number, U.S. grassland birds are among the fastest declining with a 34% loss.
Shorebirds, too, are down 33%.
It was the first comprehensive look at the nation's birds since a 2019 study showed the loss of nearly 3 billion birds in the U.S. and Canada, about 1 in 4 birds, over the last 50 years.
What to do? Start here: America's Wildlife Act, a bill passed by the House of Representatives but awaiting a vote in the Senate, would provide about $1 billion annually to states and tribes for nongame wildlife management. The grants must be used for innovative recovery efforts for species of greatest conservation need, species listed as endangered or threatened, or the habitats of such species.
Loon Migration
In a lengthy study done primarily in our area and northern Minnesota, 232 common loons were captured and banded during the summers of 2009–2016, including 204 adult and 27 juvenile loons (Kevin Kenow, et al. “Migration patterns and wintering distribution of common loons breeding in the Upper Midwest,” Journal of Avian Biology, 6/9/21).Geolocator tags were attached to the adults and 31 of them (all males) received satellite transmitter implants. The researchers recovered 111 geolocator tags from 134 of the geotagged adult loons that were recaptured or discovered as carcasses.
The satellite telemetry and archival geolocator tags were used to determine the migration patterns and wintering locations of the breeding adults and young of the year. They found that the median date of adult loon departure from their breeding lakes was from October 16 to 22. Thus, most, if not all adult common loons from Minnesota and Wisconsin are now on their way south. But in the study, the researchers found that they typically first headed east to northern Lake Michigan off of Door County, and their length of stay there averaged 27 days, often not departing until late November. They then gradually worked their way south along the lake before typically making their overland journey to the Gulf of Mexico off of Florida. Many briefly stopped at reservoirs in southeastern states, though a few stopped in Illinois, Indiana, Ohio, and Pennsylvania, finally arriving in Florida around November 26.
The chicks are left behind to fend for themselves, but the research showed that many fly from their natal lake to feed on a nearby lake which is richer in fish – they need all the energy reserves they can store up for migration. They then typically waited until close to ice-up to make the leap southward, foregoing Lake Michigan, their DNA telling them what direction to go and how far. Like the adults, however, most stopped briefly along the way at various lakes and reservoirs, and like the adults, they ended up arriving on their wintering grounds in the Gulf in late November to early December. Thus, the first fall migration of juvenile loons is much more direct and relatively quick compared to the fall migration in adults.
The study found that among the adults (103) and juveniles (23) that completed fall migration, most wintered in the Gulf of Mexico (80% of the adults and 91% of the juveniles), with smaller proportions wintering off the southern Atlantic Coast or on impoundments in the southeastern United States.
Given the likely wintering distribution of common loons breeding in the Upper Midwest coupled with the occurrence of the 2010 Deepwater Horizon (DWH) oil spill, the researchers were concerned about the effect of the spill on wintering loons. A separate study (done by Deepwater Horizon Natural Resource Damage Assessment Trustees) reported that common loon mortality was estimated from 530 to 812 individuals with additional lost productivity of 31 to 98 fledged loons during 2010 and 2011 due to the mortality of the breeding-age birds.
An aspect of common loon life history that remains largely undocumented are the causes, timing and location of mortality among young loons following their departure from their natal lakes. Survival rates of loons during their first few years of life are much lower than that of adults. Band recovery data also indicated that while some of the juvenile loons may remain on wintering areas year-round their first two years, northward movement along the Atlantic Coast during summers was common, and included distant movements to places like the Gulf of St. Lawrence and Nova Scotia.
It’s noteworthy that it’s believed that most (93%) of the breeding adult population of common loons occurs in Canada, with only 6% occurring in the United States. Of the proportion that occurs in the United States, about half are thought to occur in the Great Lakes states of Minnesota, Wisconsin and Michigan.
“Old-growth” Clubmosses
At a recent talk I gave in Stevens Point, I asked eminent retired botanist Dr. Robert Freckman about literature I’d seen over the years stating that various species of clubmosses can be very old, well over a hundred years. He amended my time frame, saying that some are thought to live 1,000 years! This was a startling revelation to me.
Nearly everyone in the Northwoods is familiar with clubmosses, but may not know them by that name. The most common is “Princess Pine,” which is absolutely not a pine, but rather, a clubmoss. All clubmoss species superficially resemble a conifer seedling to a casual observer, but clubmosses seldom grow taller than 6 inches, and they produce spores – not cones with seeds. Those who think clubmosses are tiny pine trees must wonder why they never grow up.
Clubmosses are perennial evergreens, and vegetatively reproduce by sending out “runners” along or just below the ground surface that root down at intervals. New shoots may pop up at the roots, or the stem just continues to elongate further, walking itself slowly through the woods while the tail end dies off.
In late summer and early fall, little club-shaped structures grow from the tips of the shoots in most species. Each of these “clubs” packs thousands of spores, and if you just tap one of them when they're ripe, a yellow powder billows out, catches any wind present, and the spores float to their new homestead site in the woods. Some of the clubs are on slender stalks that look like a candelabra setting for a romantic vole's dinner.
Clubmoss spores found their way into a remarkable number of early products, but most remarkable of all was the creative person who discovered the spores to be explosive, and thought to use them to produce the pan flash for old time cameras.
The clubmoss reproductive cycle closely resembles the complexity of ferns, but clubmosses belong to a group of plants called “fern allies” (sounds like NATO or something), which have the same structural characteristics and general reproductive process as ferns. The difference between ferns and their allies is that ferns have large flat fronds with branching veins, while the allies have needlelike or scalelike leaves with just one unbranched vein. In other words, the fern allies don't look a bit like ferns, and each ally variety looks quite different from all the rest – clubmosses look a bit like mosses but really more like miniature conifer trees; horsetails look like a piece of jointed bamboo often with coarse hairs; quillworts might be mistaken for clumps of grass or the long stems of young onions.
Of most importance though is the 17 or so years it takes clubmoss spores to grow through their alternate life stage and into the next generation of spore-bearing plant. Given the enormous numbers of clubmosses that are still picked every year for the wreath-making industry, clubmoss populations have suffered and their recolonization of forest areas lags well behind the harvest. If you pick them for wreaths, cut them off above the ground – do not pull them out. Better yet, make your wreaths out of balsam fir branches rather than the clubmosses. It seems only reasonable that we should not be picking plants that may be up to 1,000 years old.
Tamarack Gold
Tamaracks have fully turned gold by late October, and many are dropping their needles, or have lost all of them already. It’s the last brilliant flash of color in our rapidly fading autumn, and they’re much to be admired and grateful for.
As the oddball independent among the trees – a conifer that is deciduous – the question often arises as to why this is our only conifer that drops its needles in the fall, and it’s one that’s not easily answered. One thought is that the soft needles of tamaracks are more susceptible to snow damage and water loss than other conifers, so it makes sense to drop them.
The benefit to having needles rather than broad leaves is that they can withstand a great deal more abuse compared to leaves, and they aren't as attractive to insects. Conifers make small, sturdy leaves built for structural integrity. The leaves have a small surface area, and they’re coated with wax that reduces water loss.
The downside of this conservative strategy is that these leaves are relatively costly to make. And the structural components that make needles tough allows less room for the chemicals and cellular structures needed for photosynthesis, which is likely why evergreen needles tend to photosynthesize at lower rates than the leaves of broad-leaf trees.
Do the softer, smaller needles of tamaracks allow it to photosynthesize more rapidly than other conifers, and make the needles easier and less costly to produce in the spring, thus balancing their loss in the autumn? I’m not sure, but we are certainly the benefactors of the colorful process.
Celestial Events
To observe planets in November, look after dusk for Jupiter and Saturn in the southeast, and before dawn for Mars in the southwest.
On 11/4, look for Jupiter just a few degrees above the waxing gibbous moon. The full moon occurs on 11/8.
Thought for the Week
“An interesting question to ask yourself at night is, What did I really see this day?” – John O’Donohue.
No comments:
Post a Comment