A Northwoods Almanac for July 22, 2022

 A Northwoods Almanac for July 22 – August 4, 2022  

“In Summer, the Song Sings Itself”

            William Carlos Williams wrote that, and it speaks to the cornucopia of life that surrounds us in late July. So, let’s highlight some of all that is taking place. 

 

Breeding Animals in July?

            Most mammals bred back in late winter and early spring, but are any still breeding in July? Yes! Black bears, American martens, and weasels. Black bears mate in June to July using delayed implantation. The eggs implant in November and cubs are then born in mid-January. Adult females reach maximum size at five years and adult males at seven years, but in July, the young-of-the-year are perhaps 20 to 30 lbs. By 12 months, the cubs will reach 40 to 75 lbs; in two years, 90-150; three years, 125-200; four years, 175-250; five years, 225-300; and six years 275-350.

            American martens also utilize delayed implantation, breeding in July but the female waits 220 to 270 days until implanting the eggs in February. The eggs develop in 28 days, and once born, the young become full-grown in 3 to 5 months.

photo by Zach Wilson

            Long-tailed weasels also breed in July into August, and the females delay implantation of the eggs for seven months until March and into early April, when 6 to 9 young are born. And even though the young weasels are born altricial, meaning they are naked with their eyes closed and incapable of moving around on their own, the females grow quickly and become sexually mature in just 3 to 4 months, mating that first summer.

photo by Mary Madsen

Fireflies

            The flickering glow of fireflies occurs every night now below our house. It’s otherworldly – a bug that lights up, flashing in an orderly pattern like a little Christmas bulb to attract a mate. Fireflies contain luciferin, a chemical that, when it combines with oxygen and with an enzyme called luciferase, causes their abdomen to light up. This bioluminescence creates a light that is utterly efficient, producing no waste heat – just light and beauty.

            Fireflies are neither flies nor true bugs. Instead they are beetles, just like ladybugs.

            More than 2,000 species of firefly occur worldwide, with many species often sharing just one habitat. In fact, you are probably looking at multiple species when you are watching them in your own yard.

            The male emits flashes of light at intervals of from 5 to 8 seconds while he flies a few feet above the ground. Females wait on top of low vegetation; if a flashing male comes within six feet, the female flashes back. The exact number of seconds between flashes serves to distinguish the species. The male will only approach a light if it flashes at the proper intervals. It’s a code that lets individuals identify appropriate mates of the same species.

            Adults may live only a couple of weeks, and most do not eat during this time—they just mate, lay eggs and die. They spend most of their lives – up to two years – in a larval stage before metamorphosing into adults. 

            Be aware that outdoor lights prevent fireflies from seeing each other’s flashes, and thus, they may fail to find mates. Turn off your lights at night during firefly season to ensure you’ll have fireflies for years to come.

            On land, only a tiny percentage of life is bioluminescent, fireflies most famously, but also some millipedes, click beetles, gnats, and a few others. And there’s only one known luminous freshwater dweller – the New Zealand limpet. 

            But more than 50% of deep-ocean animals use bioluminescence for a host of purposes, from defense to luring prey to mating. Deep sea animals must find their way in the dark depths of the ocean, so bioluminescence is a practical response to the perpetual darkness.

 

Bird Parenting

            All of our nesting songbirds raise altricial young, meaning the chicks are incapable of moving around on their own or leaving the nest, and are hatched with their eyes closed, and with little or no down. However, this helpless condition changes at an incredible pace, and nearly all chicks fledge within two weeks. Some fledge even sooner – an indigo bunting chick will leave the nest in 9 to 10 days, and a hermit thrush in 12 days. Larger birds take a lot longer – a raven chick fledges in 38 to 44 days, a great blue heron in 56 to 60 days, and a bald eagle in 70 to 98 days.

            To support this astonishing growth, the parent birds have to find a seemingly endless supply of food and bring it back to the nest.  In a study of Carolina chickadees, which are very similar to our black-capped chickadees, parents have to supply 390 to 570 caterpillars every day, depending on the number of chicks. In fact, they average bringing a caterpillar back to the nest every 3 minutes. It takes 16 days or more for a Carolina chickadee chick to fledge, so in that time, the adults have to find at least 6,000 caterpillars. That’s just unbelievable! 

            In a similar study of nesting eastern phoebes, the adults had to feed four young, and made an average 526 daily visits (35 per hour for 15 hours each day) to the nest with food until the chicks fledged. The total number of visits? 8,942! 

            Where do the birds find all these caterpillars. Well, caterpillars eat vegetation, so the question comes down to what vegetation is most preferred by caterpillars? Native species are the key, because native caterpillars have evolved with native species over thousands of years. Smithsonian researchers found the key threshold is 70 percent. If a yard has more than 70 percent native plants biomass, chickadees have a chance to reproduce and sustain their local population. As soon as the number of native drops under 70 percent, that probability of sustaining the species plummets quickly to zero.

            What are the best trees to plant? One study says that in 84 percent of the counties in the U.S., native oaks are the most important tree, followed by native cherries and native willows. 

 

Goldfinches Now Nesting

            American goldfinches are our last bird to nest in the summer. There’s a close relationship between the timing of thistles flowering, which are an important food plant for goldfinches, and the start of their nest building.

 

Hummingbird Moths

            Now that flowers like bee balm (Monarda fistulosa) and Oswego tea (Monarda didyma) have come into bloom, be on the lookout for hummingbird moths who love to nectar in them. One species in particular resembles a large bumblebee – the snowberry clearwing. It’s thought that their similarity to bumblebees offers them protection from feeding birds.

            Want to try and learn more about moths and how to ID them? Try Moths and Caterpillars of the North Woods by Jim Sogaard, which introduces you to 300 of the approximately 2000 species of Lepidoptera in the Northwoods.

 

Dragonflies and Damselflies

            Over 100 species of dragonflies and damselflies breed in the Northwoods, and it’s a daunting task to learn to ID them. I’m still very much an amateur and only know a small number. Many species can be difficult to ID, but some are quite easy. I recommend learning a few easy ones first, and then gradually working your way into the more complex ones. 

            In my “easy to ID” book are chalk-fronted corporals – look for the two broad white “corporal” strips just behind the head on the front of the thorax. This species is very social and quite common along trails and on boat docks.

            The twelve-spotted skimmer is another easy one. Three large black patches mark each of the four wings for a total of twelve. And there’s a white splotch between each black patch and a pair at the base of the hindwing.

            I also find the common whitetail dragonfly easy to identify. The mature males have a strikingly white abdomen which is over half the length of their body.

            Note that just to make life complicated, the females and juveniles of dragonflies can look quite different from the males, much like in the bird world. 

            I recommend the book Dragonflies of the North Woods by Kurt Mead.

 

Spittlebugs!

            The glob of “spit” you may see on many species of trees and flowers houses the nymphal stage of the spittlebug, also known as froghoppers because of how far the adults can jump. We have three common species in the area: the pine spittlebug and the meadow spittlebug, which are found in spittle masses above ground; and the Saratoga spittlebug, found in spittle masses below ground, on the roots of plants like sweet fern and blueberry.

            The spittlebug manufactures its spit by sucking juices from the host plant and mixing them with an ingredient from its abdomen. A clear mixture is then excreted, and air is blown through the liquid by a pump-like structure beneath the abdomen, producing bubbles one at a time until the liquid becomes a froth. 

            If you gently probe through the spit with your fingers, you will find the spittlebugs enjoying another day in a controlled, almost predator-free environment.  It's an unusual but apparently effective adaptation. It doesn't offer the spittlebugs much of a view, though.

            Pine and Saratoga spittlebugs feed on new and old shoots of pines, damaging the tissue with a toxic injection of saliva. Characteristically these pines can look "flagged" with dead foliage, and may ultimately be killed.

 

Celestial Events

            On 7/26, look before dawn for Venus about 4° below the waning moon. The new moon occurs on 7/28. The peak Delta Aquarid meteor shower takes place before dawn on 7/29 – look for 15 to 20 meteors per hour, But don’t worry too much about that peak date. Delta Aquariid meteors ramble along for weeks. The Perseids aren’t too far off now – peak is on 8/12.

            And, if you haven’t noticed, our days are now growing shorter by two minutes every day.

 

Thought for the Week

            Sitting still in confined places is one of the worst punishments that can be inflicted on the human species. – Edward Hall