Phenology Report, May 3 2022
It's time for this week's installment of the phenology report! John starts us off with a wonderful validation. It's not just our collective imagination: this spring truly is one of the latest springs on record! John's friend Dallas Hudson has been tracking phenology for many years, and he and John both record the spring of 2013 as the latest in their records (with honorable mentions for 2014 and 1996). This year is rivaling 2013 for delayed springtime phenology, with some events at or approaching new records!
One such event is the flowering of the hazel. Hazels are 6-10 foot tall shrubs with light, sandy-brown catkins that grow to become 3/4-1 inch long. There are two species of hazel in Minnesota, the beaked and the American Hazel, but the timing of their development is identical (one never blooms before the other). You can find (and appreciate) the flowers by looking carefully for a tiny red dot at the ends of the buds (and we mean tiny- only a millimeter!). John found his first hazel flower of the year on April 28th; in 2013, the hazel flowered on April 29th, so we missed the record by one measly day! In any case, the hazel is blooming a full 20 days later than average (April 8th). John's finding this pattern almost everywhere. For instance, he saw his first Compton tortoiseshell butterfly last week, 18 days later than average.
On Sunday last week, it rained all day (92 hundredths of an inch, according to John's rain gauge). The ground is saturated, so vernal (seasonal) pools are beginning to form in the woods. Vernal pools (essentially big ol' puddles that form in the spring) host many species of dabbling ducks. Dabbling ducks, or ducks that tip their heads down to feed instead of diving, include teals, wood ducks, and mallards. While present in the area, you won't find diving ducks in vernal pools: the water there isn't deep enough to dive!
Instead, you'll find the diving ducks (such as ring-necked ducks, buffleheads, and goldeneyes) displaying courtship behavior in your area's lakes, ponds, and rivers. Some of these courtship displays are genuinely incredible! In contrast to the dabbling ducks, which do their courtship displays before migration, the diving ducks begin courtship once they arrive in Minnesota. So, keep an eye out for the Buffleheads, Goldeneyes, and more over the next few weeks! You'll certainly see some odd behavior.
John, the assiduous aspen observer, has finally coaxed some pollen out of the male catkins! He watched the male flowers develop for weeks, and on April 27th, the stamens were finally visible. If you can find an aspen with low branches, look for tiny red structures on the fuzzy buds: these are the male flowers. When those red structures open, you will be able to see little yellow stamens inside. The male aspens disperse pollen for a week or two; then, the flowers drop off the tree. The flowers are quite reduced on female trees: they just look like small, fuzzy buds. The pollen, borne on the wind, will find its way in to pollinate the flower. The female catkins will then begin to swell and turn green. This pattern, with the male flowers dropping off the trees after pollination and the female flowers growing, makes it very easy to distinguish male trees from female trees. Keep an eye out over the next few weeks to find out the sex of your nearby aspens!
April 29th is the average day for aspen leaves to pop out. Today, on May 3rd, there's no sign of that happening. John estimates that it'll be delayed until roughly May 18th (in other late springs, leaves have emerged 19-20 days after the first furry buds appear). In a typical spring, the events are separated 32 days; this would push the date of leaf out to June 3rd! Luckily, John assures us that won't be the case this year. He reports that late springs like this one follow a compressed pattern, with events occurring later in the year but bunched more closely together.
John's itching to get down to Crooked Lake, which is near his house! When he visited this last week, he spotted buffleheads, ring-necked ducks, mallards, and goldeneyes. The loons have flown past but not landed yet: the lake is only 20-40% open so far, but John expects that the ice will be out in the next few days (three weeks later than in an average year).
Juneberries haven't cracked open their buds yet, but if you observe them closely, you can spot long, silvery-white hairs creeping out along the edges of the bud scales. Soon, you'll be able to see green where the leaves begin to come out. If you want to see a growing green thing sooner, check out the red elderberries! Their leaves are out and growing. Our native Canada fly honeysuckle has put out its little yellow flowers. If you need help identifying it, John describes it as a plant with "big fat green buds, opposite branched and short (3-4 feet tall). The silver maples flowered last week, and the female flowers managed to survive a 17-degree morning without getting frostbitten. On the other hand, the male flowers did appear to have gotten burned (alternatively, they may have dispersed all their pollen over only a day or two). We'll be able to tell once the silver maples start to produce seeds: if they make a lot of seeds, the male flowers probably survived the cold snap.
Other signs of spring are popping up! John has seen bloodroot emerging from the ground, although it is not flowering yet. Juncos and redpolls are moving north (the redpolls are completely absent, and only a few juncos remain in John's area). White-throated sparrows have replaced them, as well as fox sparrows, tree sparrows, and more! Near the rivers, tree swallows can be seen skimming the water's surface for tiny midges (small insects that look like mosquitoes but lack biting mouthparts). As insects become more abundant, you can expect to see the tree swallows dispersing away from the river and moving into bluebird houses. John heard 4 to 5 peeps from a spring peeper, but only once and just one individual. Ruffed grouse, in contrast, are drumming up a storm! He heard eight drummings in a half-hour yesterday and is confident it was several individuals.
On a sad note, John's resident bald eagles had a nest failure this year. On a cold, wet morning last week, he noticed both eagles soaring off in the distance; this was a bad sign, as the eagles would not leave the eggs or nestlings out in those conditions. Unfortunately, John is now confident that this year's eggs either didn't hatch or the nestlings died. The eagles have abandoned the nest, though they remain in the area. Over the last 35 years, it's been very rare that the eagles have failed to raise offspring, but this is one of those sad years!
John brings us a few other noteworthy items of interest. This year, the average temperature in April was 34.8 degrees, with a low of 15 and a high of 58. Last year, April averaged 41.9 degrees, with a low of 22 and a high of 75! That's a solid 7-degree difference in average temperature between the two years. Finally, he notes that snow cover in the forests is down to less than 5%, and he only has a few snowbanks remaining. He expects they'll melt very soon with the warm weather coming up.
John says the next week will be fantastic for phenology: keep your eyes out! Look particularly hard at your red maples, tulips, and dandelions (especially on the south side of your house). This might be the week that spring finally shows up in northern Minnesota!