Tag: bird

Bug o’the Week – Common Aspen Leaf Miner

Bug o’the Week
by Kate Redmond

Common Aspen Leaf Miner

Greetings, BugFans,

Leaf miners have been mentioned in these pages before – even the Aspen leaf miner (Phyllocnistis populiella) has appeared briefly.  When she did a little more research, the BugLady was ecstatic to discover that Aspen leaf miners have an association with EFNs, one of the coolest things she’s ever found out about in her 16 years of writing BOTW (more about that in a sec).  Here’s its story.

First of all, a quick and dirty leaf miner review.  They are (primarily) the tiny larvae of a variety of species of fly, beetle, moth, or sawfly (Hymenoptera), and they are everywhere.  They mostly feed on sap or tissue that they encounter as they chew their way around inside a leaf, between its top and bottom layers, some feed in fruit, and some can process plant tissues that are toxic.  Leaf miners are found on plants in most plant families (as J. R. Lowell once said, “There’s never a leaf nor a blade too mean to be some happy creature’s palace.”), and some are extreme specialists, using only one or just a few plant hosts.  They are often active in mid-to-late summer, and they transform plant energy into animal energy for the birds and insects that know their secret hiding places.  

They create distinctive patterns that, along with the identity of the plant, help us to name them.  Mines are roughly divided into three categories – serpentine, blotch, and tentiform.  Most mines and their miners do not cause significant damage to their host – as J. G. Needham said in “Leaf-mining Insects” (1928), Not only does their minute size partially excuse them, but in feeding habits most are very precise and economical of tissues.  They take just enough to sustain and mature their own lives, and they injure little tissue save that that they ingest.”

Leaf miner is more a culinary and lifestyle grouping than a scientific/taxonomic classification.  For more background on leaf miners, see https://uwm.edu/field-station/bug-of-the-week/leaf-miners/. 

There are a dozen members of the genus Phyllocnistis (from the Greek meaning “leaf scraper”) in North America.   They’re in the family Gracillariidae, the Leaf Blotch Miner Moths, and they are small and fringed, with wingspreads under ½,” (“micromoths” – another not-quite-scientific designation).  Their larvae, flattened and rudimentary, spend their first three instars chewing serpentine trails in the leaf tissue, guzzling sap, and leaving behind a trail that’s punctuated by a line of frass (bug poop) (an “instar” is the active, feeding stage between molts).  The larva doesn’t feed in its fourth and final instar; it gets itself to the margin of the leaf, where it spins a cocoon and pupates in a spined pupal case (some kinds of leaf miners drop to the ground to pupate, but not this bunch).   

The Aspen leaf miner stars in a number of Extension horticultural bulletins, but its impact, other than cosmetic, tends to be minimal.  If there’s a black sheep in the genus, it’s the Citrus leaf miner https://bugguide.net/node/view/1318589/bgimage.

COMMON ASPEN LEAF MINERS, aka Aspen serpentine leaf miners, are found across southern Canada and the northern half of the US, wherever quaking aspen grows.  Some sources said that poplar and cottonwood are also used as hosts, and some said that the main host is aspen, and some said that mines found on cottonwood and poplar are made by a different species.  The tiny moths have pale, narrow wings and long-ish antennae, and they often perch slanted, with the front half of their body “on tiptoe” https://bugguide.net/node/view/1582507/bgimage.  

For a small, relatively harmless insect, there’s a surprising amount of biographical information available.  They overwinter as adults, avoiding freezing through careful selection of a winter shelter and because of their ability to supercool themselves, dropping their freezing point.  Counterintuitively, they prefer to overwinter under spruce trees rather than aspens, because the deeper snow cover below the aspens translates to wetter conditions as the air warms, and ice in a late freeze.

Romance blossoms in spring, and females lay their eggs on the edges of emerging leaves, near the tip, usually only one egg per leaf, and then they fold the edge of the leaf over to protect the egg until it hatches.  When it does, the larva https://bugguide.net/node/view/204391/bgimage, chews through the floor of the egg, directly into the leaf, where it will live until it emerges from its pupa as an adult in fall.  

Larvae eat the sap that they generate while tunneling.  A research team tracked the mining habit and found that:

  1. A single caterpillar may mine an entire small leaf https://bugguide.net/node/view/30617/bgimage, but only part of a large leaf until it has consumed enough calories to pupate;
  2. When the larva gets to the midrib, it turns toward the leaf’s base, and when it gets there, it turns again and follows the leaf margin for a while before heading for the midrib again;  
  3. Sometimes more than one egg is laid on a leaf.  A larva may not know that it has company in the leaf, but if two larvae discover each other, they generally feed and pupate on opposite sides of the midrib;
  4. They don’t re-mine an already-mined trail;
  5. Larvae pupate at the edge of the leaf.

Heavy feeding on the epidermis of a small leaf can interrupt its photosynthesis, causing leaves to dry, turn brown, and fall prematurely, but aspens have lots of leaves, and the Common aspen leaf miner larvae, as Needham said, don’t eat much. 

Adults https://bugguide.net/node/view/1128097/bgimage feed on nectar that they find in extrafloral nectaries (EFNs) at the base of the leaves (between one-third and three-fourths of aspen leaves have them).  Here’s a BOTW about EFNs – https://uwm.edu/field-station/bug-of-the-week/ants-in-my-plants-rerun/. 

And here’s “Leaf-mining Insects” by J. G. Needham, et al, https://www.biodiversitylibrary.org/item/28922#page/7/mode/1up

The BugLady saw a Common Green Darner last week – let the Wild Rumpus begin!!

It’s Earth Day/Week – remember, there’s no Planet B.

Kate Redmond, The BugLady

Bug of the Week archives:
http://uwm.edu/field-station/category/bug-of-the-week/

Bug o’the Week – And Now for Something a Little Different III – Timberdoodle redux

Bug o’the Week
by Kate Redmond

And Now for Something a Little Different III Timberdoodle redux

Howdy, BugFans,

This episode was originally adapted from the Spring, 2010 issue of the BogHaunter, the newsletter of the Friends of the Cedarburg Bog, written by the BugLady wearing a different hat.  It’s further revised from a BOTW of seven years ago – new words and new pictures.

Woodcocks are wonderful birds with a great story.  They were a big part of the BugLady’s childhood – their return to our brushy fields was celebrated each year and it was (and still is) a race to see who would hear the first one (thanks, Mom, thanks, Dad).

American Woodcocks (Scolopax minor), family Scolopacidae, are long-billed, big-eyed, short-legged, round-winged, Robin-sized birds.  The Cornell University All about Birds website says “Their large heads, short necks, and short tails give them a bulbous look on the ground and in flight.”  Woodcocks are a dumpling of a bird – about 10 inches long, weighing up to a half-pound, with big eyes, very short legs, and a very long bill (2 ½” to 2 ¾ “).  Females are larger than males and have longer bills, too. 

Woodcocks are shorebirds that are not tied to the shoreline – upland game birds, the “Landlubbers” of the shorebird family.  These odd-looking birds (the BugLady has read that hunting dogs find them odd-smelling, too) have many nicknames, like “timberdoodle” “mudbat,” “brush snipe,” “bog-sucker,” “hokumpoke,” and “night partridge.”  

A look at where a woodcock lives and what it eats explains its adaptations.  Short, wide wings are perfect for flight through close, brushy areas.  A woodcock is a bundle of adaptations.  Short wings make it easier to maneuver in the brushy fields, woody edges, wet meadows, and open woodlands that they call home, and the fact that they are able to fly slower than any other bird – 5 MPH – serves them well in those spots. 

Their superb camouflage makes it impossible to spot them before they fly, so most views are rear views as they exit the scene.  The BugLady once unknowingly stood near two young birds for about five minutes until they couldn’t stand it anymore and departed, startling her with their whistling wings (there have been some interesting studies of birds’ tolerance of nearby humans – birds are more distressed by someone who stops than by someone who strolls by). 

Most of their adaptations have to do with their feeding habits.  That long bill allows a woodcock to extract earthworms and other invertebrates (snails, millipedes, spiders, flies, beetles, and ants) from deep in the moist soil.  The tip of the bill is both flexible and sensitive and can be opened without opening the base.  Worms are slippery little devils, and roughened surfaces on the tongue and upper bill help the bird to get a grip.  Which is a good thing – a woodcock may eat its weight (about a half-pound) in worms daily.  They also eat some plant material – seeds, sedges, and ferns.  They feed during the day, solo, during breeding season and at night on their winter grounds.  Here’s a video of a woodcock foraging https://www.youtube.com/watch?v=swHtEAEfGXM&ab_channel=CornellLabofOrnithology.   

The woodcock’s typical rocking walk was explained by early ornithologists as a tactic to produce vibrations that would rouse earthworms into motion so that the woodcock could hear them.  Later biologists speculate that the slow gait tells potential predators that the Woodcock knows they’re there (and is in no hurry).  See https://whyevolutionistrue.com/2021/02/28/why-do-woodcocks-rock-when-they-rock/ (but don’t turn on the audio).

Any animal that feeds with its head down runs the risk of becoming a meal while having a meal.  Over time, woodcock eyes have migrated toward the top of their head.  As a result, woodcocks have good vision both in back and to the sides while they probe for worms (as opposed to a robin, which has eyes on each side of its skull and can’t see much to the fore or aft).  Because their eyes have thus migrated, their brains have been rearranged and are upside down. 

But, they’re famous for something besides their looks. 

Woodcocks make their presence known in early spring – often by mid-March – when males take to the air to perform their amazing “sky dance.”  They begin around sunset and continue into the wee hours, especially if the moon is full – the BugLady has heard them in her field at 1:00 AM.  The dance is repeated at dawn.

After calling from the ground for a while – a nasal sound described as a “peent” https://www.youtube.com/watch?v=4Owj52XhoxI – the male takes off.  Specially-shaped wing feathers produce a twittering sound as he spirals into the air, sometimes more than 300 feet up.  From high in the sky, he zigzags back down, vocalizing a rich “chirp, chirp, chirp, chirp” sound.

Let Aldo Leopold tell it: “Up and up he goes, the spirals steeper and smaller, the twittering louder and louder, until the performer is only a speck in the sky. Then, without warning, he tumbles like a crippled plane, giving voice in a soft liquid warble that a March bluebird might envy. At a few feet from the ground, he levels off and returns to his peenting ground, usually to the exact spot where the performance began, and there resumes his peenting.” 

There, the theory goes, the enamored female woodcock will find him. 

The first sound on this audio is the chirping call of a descending bird https://www.allaboutbirds.org/guide/American_Woodcock/sounds, and if you listen, after he’s landed and is peenting, you can hear the faint “Whoop – Whoop” sound that apparently is a communication between two birds that are on the ground.  More vocalizations can be heard in the “Sound and Calls” section at http://www.audubon.org/field-guide/bird/american-woodcock.

Once she finds him, he struts and bows with outstretched wings.  Females may make the acquaintance of several males, and vice versa, but by the end of April, the show’s about over.  Males will continue their sky dance into early May – even though most of their potentially appreciative audience is sitting on eggs.  They are often incubating during the final snowstorms of spring.  Hope springs eternal, and some females will join the dance even while they’re caring for young. 

Woodcocks nest on the ground; females line a shallow depression with leaves and deposit (usually) four mottled, tan eggs in it.  She will sit on them for about three weeks, but the male does no incubation or child care.  The young are “precocial,” (think “precocious”) – unlike the blind and naked young of songbirds, woodcock nestlings are dried off and running around within hours of hatching.  Although she continues to feed them for a week or so, the young are probing for food when they’re just three or four days old, and flying after two weeks.  Fun Fact – newly-hatched Woodcocks have adult-sized feet. 

As ground-nesting birds, woodcocks are preyed on by dogs, cats, skunks, possums, and snakes.  The BugLady once saw a woodcock fluttering across a field, just above the grass tops, pursued by a raccoon; it may have been a female, leading the raccoon away from her nest. 

Many birds undertake epic migrations, but not the Woodcock.  As the ground chills and worms migrate vertically to escape the frost, woodcocks need only travel to the Southeastern and Gulf States, where unfrozen ground allows them access to food.  Woodcocks migrate at night, at low altitudes, alone or in small groups, usually starting in October.  The trip is unhurried, with the birds’ cruising along at about 25 MPH.  They start the return trip in February.

Around the beginning of the 20th century, books were being cranked out by “nature-fakers,” who romanticized and anthropomorphized the daily lives of the animals they wrote about.  They wrote that a woodcock was able to set its own leg if one got broken – the proof being the crusted mud often seen on woodcocks’ legs. 

Lots of Nature Centers offer Woodcock Walks at this time of year, or you can drive out into the countryside and find a brushy field.  The show usually starts about 45 minutes before sunset.first&year=2025.Fritillary https://bugguide.net/node/view/1990523/bgimage, https://bugguide.net/node/view/1887246/bgimage, give it a second look, just to be sure. 

Kate Redmond, The BugLady

Bug of the Week archives:
http://uwm.edu/field-station/category/bug-of-the-week/

Bug o’the Week – And Now for Something a Little Different XVIII – Red-breasted Mergansers

Bug o’the Wee
by Kate Redmond

And Now for Something a Little Different XVIII Red-breasted Mergansers

Howdy BugFans,

Perched, as she is, on the rim of the Lake Michigan, the BugLady has a front row seat for the activities of the Lake and its residents (and, of course, she’s photographing the heck out of it – rainbows, sunrises, sunsets, storms, ships, and this fall, even waterspouts!).  The Lake changes daily – hourly – in minutes.  In fall, and then again in late winter, flash mobs of mergansers and gulls erupt and then disappear, following schools of small fish.  It’s hard to tell whether the mergansers locate the fish first and the gulls notice, or vice-versa.  Once, the BugLady watched as two Bald Eagles flew out to investigate the scrum.

This year, toward the end of November, she watched a raft of mergansers more than 100 yards long (she couldn’t photograph the whole line) – many thousands of ducks, plus gulls, diving for fish.

So – what are Red-breasted Mergansers?

Winter brings Red-breasted Mergansers to Lake Michigan, flying low in long strings, far offshore. Mergansers, along with about a dozen other species, belong to a group of ducks called the Sea, Marine, or Diving ducks (as opposed to the Puddle or Dabbling ducks like Mallards and Teal). Sea ducks are mostly northern species that are adapted to survive offshore in winter, and many dive deep for their food.  

Drinking salt water (or consuming it with their prey) is as bad for sea ducks and other oceanic species (petrels, shearwaters, etc.) as it is for us, but they have a salt gland located above each eye that acts like a mini-kidney, filtering salt from the water and releasing concentrated salt water through the nares (nostrils) https://travisaudubon.org/murmurations/salt-glands-in-seabirds.

Red-breasted Mergansers (Mergus serrator) are one of three species of mergansers in North America; the others are the Hooded Merganser and the Common Merganser, known in Europe as the Goosander. Of our three mergansers, the Red-breasted Merganser is found more often in salt water, and it breeds farther north and winters farther south than the other two. Red-breasted Mergansers are sometimes called “sawbills” (“serrator” comes from a Latin word meaning “sawlike”) because of the serrations on their bill that help them grip fish.   

They are native to northern Eurasia as well as North America; here, they breed on both the Atlantic and Pacific Coasts, and across Canada and the northern tier of the US. They winter in the Great Lakes and along both coasts south to Mexico.

Like loons and the other Sea ducks, their legs are located near the rear of their body –- great for propelling them under water, but not so great for walking. Unlike Puddle ducks, which can leap into the air from the water, Sea ducks must run along its surface, flapping, in order to take off.

Red-breasted Mergansers spend about half of their waking hours looking for food. They primarily eat small fish, but their menu may also include fish eggs, crabs, aquatic insects, and tadpoles, and because they like small salmon, some have been known to “adopt” fish hatcheries. They hunt by swimming along with their faces just below the water’s surface, like a snorkeler, and by diving (they can stay underwater for about 45 seconds), and sometimes a group of mergansers will cooperate to herd a school of minnows. They typically forage in relatively shallow areas, but they’re equally at home in deep water.  

Male Red-breasted Mergansers court by dips, head shakes, and curtsies, vocalizing with a soft “yeow-yeow” sound (here are some merganser vocalizations – https://www.allaboutbirds.org/guide/Red-breasted_Merganser/sounds). Females nest beside fresh or salt water, often close to the area they were hatched in, and because they are a social, non-territorial species, they are comfortable nesting near gulls or other ducks. In June, females lay their eggs in a shallow depression lined with grass and feathers, but males don’t stick around to help with the incubation. Females lead the ducklings to water within a day of hatching, and they are on their own just a few weeks later. They can fly when they’re about two months old. 

The clutch size is five to 24 eggs, but other females may contribute their eggs (conspecific brood parasitism), and nests with fifty or more eggs have been found. Mergansers that nest near other mergansers may combine their broods after hatching –- the mass of ducklings is called a “crèche” or “nursery” –- and females take shifts supervising them.

Cold weather kills about half of each year’s crop of ducklings, and predators of eggs and ducklings — ravens, gulls, jaegers, and mink — kill another quarter, but if a duckling survives to adulthood, it’s liable to live for another five or six years. Adults are eaten by foxes, Great-horned and Snowy Owls.

Like other Sea ducks, they are fast flyers; one Red-breasted Merganser was clocked at 100 mph (by the plane that was chasing it).

They are hunted by duck hunters in many areas, but because of their diet, they don’t taste very good (“inedible,” say some bloggers). Most recipes for Red-breasted Mergansers involve removing as much of the fishy-tasting fat as possible, marinating what’s left, and then cooking it at for a long time with lots of herbs.

As long as there’s not too much boat activity, the Port Washington Harbor and adjacent Coal Dock Park can be great places to watch Red-breasted Mergansers and other waterfowl in winter, along with several species of gulls.

The BugLady originally wrote this article for the newsletter of the Lake Michigan Bird Observatory. in her storage unit, and she found an earwig on her sink, but she’s pretty sure that it, like the tree frog that was in the shower, came in when she brought the geraniums inside for the winter).

Kate Redmond, The BugLady

Bug of the Week archives:
http://uwm.edu/field-station/category/bug-of-the-week/

Bug o’the Week – And Now for Something a Little Different XVI – Turkey Vulture

Bug o’the Week
by Kate Redmond

Bug o’the Week And Now for Something a Little Different XVI – Turkey Vulture

Howdy BugFans,

The BugLady hangs out on a tower by Lake Michigan from the beginning of September until the end of November, logging migrating raptors as they navigate south along the shoreline (up until this week, she was still seeing a few Monarchs and Common Green Darners, too).  She already misses the comforting presence of Turkey Vultures – 99.9% of this fall’s migrating Vultures have made their way past the hawk tower – she loves looking way out over the fields and seeing them rocking back and forth over the woods, taking care of business.

She wrote this biography for the newsletter of the Lake Michigan Bird Observatory (the organization formerly known as the Western Great Lakes Bird and Bat Observatory), an organization that would appreciate your support.

A sit on the hawk tower in mid-October of 2021 turned out to be a religious experience. Though they are not technically birds of prey, we do include migrating Turkey Vultures (TVs) in our Hawk Count, and of the 789 raptors of 10 species that passed by the tower on that amazing day, almost half were TVs! The vultures approached in groups of 15 to 30 birds, circling on warm updrafts as they moved south. As one group passed, two or three more could be seen approaching us from the north.  

Turkey Vultures get their name from dark plumage and bald, red heads that are reminiscent of Wild Turkeys. They’re also called buzzards. “Vulture” probably comes from the Latin “vellere,” which means “to pluck or tear,” and their scientific name, Cathartes aura, means “golden purifier or cleanser” (being eaten by a vulture after death was believed in some cultures to cleanse and release one’s soul). The Cherokees referred to TVs as “Peace Eagles” because although they look like eagles, Turkey Vultures don’t kill their food.    

Turkey Vultures are one of six species in the New World Vulture family Cathartidae, and they are not related to the vultures of Europe and Asia. Three of those New World species — the TV, Black Vulture, and California Condor — are found in the US. Turkey Vultures are the most widespread of our vultures, found from southern Canada into South America, and data suggest that their range is spreading to the north.

They’re generally found in open or semi-open country rather than in heavily wooded areas, and they are tolerant of human activity and of landscapes altered by man. Construction of Wisconsin’s interstate highway system began in the late 1940’s, and one source pointed to the subsequent increase in road kills as a cause of higher numbers of TVs here in the second half of the 20th century.   

These are big birds, with bodies about 30” long and wingspans of six feet. They are about three-quarters the size of a Bald Eagle, but at a maximum of four pounds, they are less than half an eagle’s weight, and they lack the strong, gripping talons of eagles and hawks. Most of their feathers are dark brownish gray, and in flight, the leading edge of their wing is dark and the trailing edge is silvery. Males and females look the same, and young TVs have gray heads. They do lots of soaring and not much flapping, their wings held in a wide “V” called a dihedral for stability, and they often tip back and forth.  

Turkey Vultures don’t have a voice box (syrinx), so their vocalizations are mainly grunts https://www.audubon.org/field-guide/bird/turkey-vulture and hisses https://www.allaboutbirds.org/guide/Turkey_Vulture/sounds that are used to startle intruders. 

Although they bathe frequently, people who get close to them will testify that vultures stink — partly because of their diet, and partly because when they’re hot, they excrete urine on their legs, which cools them as it evaporates and also disinfects their legs (it’s called “urohydrosis“).  

TVs are scavengers (“recyclers”) that mostly feed on dead mammals, though they will eat other dead vertebrates, and they are thought to eat more than 100 pounds of meat a year. They also feed on vegetation. They use their keen eyesight to locate carcasses, but vultures are also one of the few birds that have a good sense of smell, and they count on both senses as they fly low over roads and fields (and dumps and dumpsters) — they can sift out the odor of decay from a mile away. Like owls, they spit up pellets of indigestible bones and fur. TVs rarely take live prey, but Black Vultures do kill some newborn livestock and the occasional small pet.  

The amazing thing about Turkey Vultures’ food habits is that no matter how old the carcass or how riddled it is with bacteria, botulism, cholera, or other such organisms, their immune systems protect them from getting sick. Even more amazing is the fact that pathogens that are neutralized by the vultures’ highly acidic digestive juices (the pH is less than 1) are not present in their droppings! And, according to an article on the National Audubon Society website, “immensely powerful acids in the vultures’ gut begin digesting the flesh so thoroughly that they even destroy the prey’s DNA.” In addition, while they destroy some microbes, the birds apparently filter out some of the ingested bacteria and put it to work in their guts. The end result is that vultures reduce the amount of highly toxic pathogens in the environment, so, the cultural idea of being cleansed by being eaten by a Turkey Vulture has some biological truth.

During courtship, a group of TVs gather on the ground and hop around in a circle in a stylized dance with their wings spread (something this writer would dearly like to see!). They also perform “follow flights” in which one bird leads the other through elaborate aerial maneuvers. Pairs stay together for a long time, both on their breeding and their wintering grounds. 

Turkey Vultures lay one to three eggs in a slight depression that they scrape into the ground under bushes, in caves, hollow logs, and old buildings. They will use abandoned hawk nests, and they’ll reuse successful nest sites. Incubation lasts about five weeks, and after they hatch, the chicks are fed regurgitated food by both parents. They can fly at nine or ten weeks and are soon independent.

While their populations seem to be stable, Turkey Vultures are susceptible to collisions with power lines and other structures, with fences, and with cars as they gather at road kills. Poisoned baits, lead shot ingested from dead animals, and deliberate shootings are also mortality factors. They are protected by the Migratory Bird Treaty Act. 

Fun Facts about Turkey Vultures:

  • Through the years, the New World vultures have been classified with the falcons, with the storks and herons, and in their own order, but the latest DNA-sequencing seems to put them, for now, with the non-falcon birds of prey. 
  • When predators approach, TVs, young and old alike, defend themselves by projectile vomiting, sending a stream of caustic, semi-digested rotten meat as far as 10 feet away.
  • They may perch with wings outspread to warm up in the morning, to cool off during a hot day, or to dry wet feathers.
  • TVs like company –- they roost, soar, and migrate with other TVs. 
  • They are smart and curious, and in captivity will play games with their caretakers (in Wisconsin, you must be licensed to take a wild animal from the wild).

The BugLady is looking forward to their return in spring.

Kate Redmond, The BugLady

Bug of the Week archives:
http://uwm.edu/field-station/category/bug-of-the-week/

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