Archive | wildlife RSS feed for this section

Flying High

6 Nov

Last night on the way back from town, I observed and drove along with a flock of ~250-300 sandhill cranes returning to the refuge from foraging north of here. (Couldn’t do an accurate flight count and drive at the same time.)

Observing the flight dynamics of this group was really quite interesting. Unlike Canada geese that typically form several dynamic ‘V’ patterns, this flock of cranes did not. Except for the front ‘V’ with a very truncated side ‘arm’ of five individual cranes, the rest of the flock was one long linear flock stretching for a few miles.

Typically with geese the front leading bird of the ‘V’ formation frequently changes, trading places with nearby individuals. This seems logical because energy is then conserved among the leading birds. Not so with this flock. The leading crane never left its position as lead and never ‘coasted’ in flight, aka never altering or ceasing wing-flap flight. I was impressed, but also suspected it was very energy consumptive. Additionally, the five cranes forming the truncated arm behind the leader never changed positions and also never faltered in consistent wing activity.

The cranes following in line behind the leader, on the other hand, often coasted with short periods of folding wings alongside their bodies. Whether this was to rest (energy conservation) or to retain their position in the long line, I cannot be sure. I did notice that some individuals did change positions when some birds slowed or fell slightly out of line. Consequently, the line was truly maintained as one long linear fight pattern! I also wondered how many of these birds were immature cranes who aren’t yet as strong as the older adults, or if they haven’t yet mastered the ‘protocol’ of flying in large flocks. I watched one crane fly under and ahead of five other cranes in front of its former position and fill in a gap in the line. It reminded me of how blackbirds and other flock songbirds change positions while roosting on utility lines, with some hop-scotching to keep a tight and consistent line formation.

I was fascinated by the flock and flying dynamics of these several hundred sandhill cranes! Very different from the geese. Although my original intent was just to monitor where this flock landed, I was treated to an entirely different perspective of flock flying dynamics.

Because questions of daily roosting versus feeding movements and populations of sandhill cranes arose during a meeting between state and federal managers this week, I thought watching where this flock was destined might be interesting. Only a small percentage of the total flock (~24) landed on the small ‘crane ponds’ (small shallow water impoundments just north of the main refuge where cranes often roost). I expected a higher sub-set of this flock to land there. I briefly watched these birds try to locate the members of their family units for roosting overnight, then I drove ahead to monitor the remainder of the flock.

As the larger sub-set of birds approached the center of the refuge where two large impoundments are shallowly flooded for roosting and feeding, the linearity of the flock dissolved as smaller flocks formed and dispersed. Approximately 50% of the flock settled on these impoundments, and the other 50% flew east to roost on the sandbars of the Rio Grande River.

New Mexico state biologists survey populations of waterfowl on the river via aerial surveillance once a month. This refuge conducts feeding surveys every week. We are discussing now whether to incorporate ground roosting surveys for geese and cranes once or twice/month to add to the total data on use of the resources and land in the mid-Rio Grande Valley, especially since most of the cranes now present here are flying north to feed during the day at state-managed refuges (~38 and ~60 miles north of here).

Estimating the light geese roosting population would be easier than that of the cranes because the former typically take flight in one large massive flock. Cranes, on the other hand, usually depart from their overnight roosting places in small family units of 2-4. However, cranes congregate in overnight roosting  flocks at only a few locations on the refuge. Counters posted at each of these locations can easily count the family units and obtain total numbers as they take flight. It might take longer, but it might also be more enjoyable.

dsc09839

Feeding sandhill cranes at Bosque del Apache NWR

Wings of mimicry

17 Sep

dscn1812-m

The early rising sun greeted us with a visitor in the damp grass one morning of a camping trip near New York’s Thousand Islands. As sunlight glistened on the blanketing dew, this large winged visitor rested on the grass waiting for moisture to evaporate off its wings and the sun to warm its body. It reminded me of another large moth, the luna moth (Actia luna), that I knew well during my life in the Maine woods.

The moth found on the wet grass that morning was a polyphemus moth (Antheraea polyphemus). Both moths are of the Giant Silkmoth family (Saturniidae). With a wingspan of up to six inches or more, the polyphemus moth is about the same size as a luna moth. These two species are the largest moths in continental America and may be found from Canada to northern Mexico.

dscn1816-s

Male polyphemus moth (antenna are larger than female’s)

Polyphemus moths are generalists, which means they do not require a specific species of plant for the larvae to develop and survive. Females lay flat brown eggs on many species of decidous trees: elm, birch, willow, maple, beech, locust and a variety of Prunus species (cherry, plum, peach, etc). Like many Lepidoptera, polyphemus larvae develop through five stages and molts (instar). Unlike monarch butterflies, of which the instars are very similar in coloration, these moths have slightly different coloration with each instar. The fifth and final instar is an average of four inches long and a bright green color with silver spots on its sides. A caterpillar can devour about 86,000 times its weight from emergence to full development in two months.

From the photos of the adult moth below one can see hair-like body scales, small head and mouth parts, and the eye spots on the wings. Because of their small mouth parts, adults do not eat and only live for a week or less, during which their entire purpose is to avoid depredation and reproduce.

Mimicry

Mimicry throughout the animal kingdom is an example of natural selection in evolution. Ranging from mammals to tiny insects, mimicry may increase survival of individuals in their environment. Or it may reduce survival in another environment.

Lepidoptera are fascinating examples of how mimicry enables survival. One tactic is to mimic another insect that may be undesirable prey. Another tactic is the patterns and structures on butterfly and moth wings that mimic a component of their environment to hide from depredation. These tactics may be adaptive defense mechanisms (or artifacts of other patterns of coloration) in response to threats. Our polyphemus moth will serve as an example of mimicry as a defense mechanism.

Distraction Pattern

Like many saturniids the polyphemus moth has large ‘eye spots’ on its hind wings. These wing eye spots are translucent ‘windows’ which may be surrounded by bright colors. The pair of eye spots on the polyphemus hind wing are bordered by bright colors and, with the entire wing pattern, may resemble eyes of a predator. These are distraction patterns, which is a form of mimicry. They may resemble eyes of a different animal and confuse or deceive potential predators.

Wing eye spots can be a form of self-mimicry and a distraction pattern: to draw a predator’s attention away from the most vulnerable body parts or to appear as an inedible or dangerous animal. When threatened, adult polyphemus moths flash their  wings exposing the large hind wing eye spots to distract, startle, or scare off potential predators.

dscn1814-m

The centers of the eye spots lack scales, so they are transparent.

Another example of distraction pattern in mimicry is camouflage which helps avoid detection by predators. Eye spots and wing color patterns on adult polyphemus can serve as blending camouflage (color matching) and pattern camouflage (pattern matching) in their environment.

Unrelated to mimicry, these eye spots may also play a role in mate attraction, but this has not been conclusively confirmed.

dscn1811-sMimicry is also exhibited by the polyphemus caterpillars. They can be protected from predators by their cryptic green coloration (another example of what kind of distraction pattern?). When threatened the caterpillars often raise the front part of the body up in a threatening pose. If attacked, the caterpillars make a clicking noise with the mandibles.  This clicking is associated with a distasteful fluid exuded by the caterpillars which can cause regurgitation by the attacker. Some animals (squirrels, birds, other insects) are deterred by the ingestion and regurgitation and the clicking may serve as a warning.

Mimicry and names

Since one of my interests is the etymology of animal binomial names (simply put, the naming of things), mimicry also plays a part in this moth’s name.

The four silkmoth species in the New World (the Americas) were assigned to either Telea or Metosamia genus. The polyphemus silkmoth in the Americas was first described and named by Dutch naturalist Pieter Cramer in 1776 as Telea polyphemus. Jacob Hübner, a German entomologist (1761-1826), assigned the Old World (endemic to Asia and Europe) silkmoths to the genus Antheraea in 1819.  In 1952, American entomologist Charles Duncan Michener (1918-2015) systematically categorized the Telea and Metosamia in with Antheraea classification. All the silkmoths are now in one genus classification.

The Modern Latin genus name Antheraea likely derives from the Greek anthēros, meaning brightly colored, brilliant, or flowery.  The Lepidoptera Antheraea type species (the species on which the description of a genus is based on, and with which the genus name remains associated during any taxonomic revision) is the beautiful and vibrantly-colored tasar silkworm (Antheraea mylitta, formerly Phalaena mylitta), named and characterized in 1773 by English entomologist Dru Drury. Although not a silkworm like the tasar species, the polyphemus is colorful and has similar eye spots.

Cramer’s choice of the species name was based on Polyphemus, the giant cyclops from Greek mythology who had a single large, round eye in the middle of his forehead. Cramer may have been reminded of the name because of the large eye spots in the middle of the hind wings.

And the commonly used name ‘sphinx’ moth?  It could have arisen because of the behavior of threatened larvae. When they raise their heads and thoraxes up, the pose superficially resembles Egyptian sphinxes. Someone had imagination.

Of course, the family name Saturniidae  also peaked my curiosity.  The consensus is that it was based on the eye spots of some members of the family that contain concentric rings reminiscent of the planet Saturn. I’ll take that, too.

 

Nature in Photography

6 Feb

A week or so ago on FaceBook I was nominated by two friends to participate in the #challengeonnaturephotography meme. Although I rarely participate in these memes, the thought “Why not?” prompted me to give it a try. The protocol is to post a nature-themed photograph, include the hashtag, give kudos to the friend that nominated you, and then nominate another friend in the caption.

I played by the rules for three days. Then life got in the way (long days in the field), and I got lazy. I posted when I had time, dropped the official hashtag, the nominators, and ran out of FB friends to nominate. I keep my FB friends to a relatively small number (up to 50 now!), and friends who are into photography have already participated once or twice.

Now I submit a story with the photograph instead. Why? Because photography to me is a storytelling medium. Today’s photograph is a glimpse into the secret lives on the ‘little people’.

Nearly every day for three months last summer, I was privy to an entire world few of us see in depth and detail. I felt like a giant studying, learning, and enjoying a network of soil, water, plants, and insects……….at their level. Sometimes I was so giddy with childlike delight, I forgot who and what I was. And I was full of anger and intense sadness when part of this magical world was destroyed by humans. That, too, was a lesson I won’t forget.

Revealed below is a monarch butterfly larva and several cobalt blue beetles all ‘doing their thing’. They use milkweed as a common food source. Yet they tolerate each other. I have watched members of both species consume leaf material, side by side without conflict. Here, two beetles are copulating, undisturbed and unfettered. While the monarch voraciously chows down, preparing to form its chrysalis. This, however, is only one tiny window into the lives that live in the ecosystem in which I immersed myself.

Most nature photography depicts landscapes of empty agents and actors. Or portraits of animals, still and silent in pose like a person sitting for a photograph. To me this is an injustice to the inhabitants of the landscape as they live out their drama and narratives in those spaces. Few ‘nature’ photographs reveal the complex interrelationships within the landscapes and with their fellow animals. They fail to show the communities of life in places other than within our own human preconceptions and expectations. As if we strive to capture and show only a snapshot in time and space that suits what we want to see.

In addition to the beauty, the silence and solace depicted in landscape and wildlife portrait photography is a dynamic world of creatures living their lives just like we do. The drama, the beauty, the good and bad, birth and death, at every level; from micro to macro. There are stories out there that are not of our own.

And we can learn from them: About their lives, their interactions with each other and how we interact with them. We can even learn about ourselves.

Think about that the next time you are out in the natural world. Take time to observe before you press on that shutter release button. You never know what you might find.

image

Fifth instar monarch larva and cobalt blue beetles on showy milkweed.

An encounter with a young hawk

29 Jul

I heard a nearby truncated shriek. A familiar sound, but lacking the usual power and strength. Scanning the area around me, I saw a silhouette that, again, was a familiar shape.

Underneath the wide umbrella canopy of an old tree, sheltered from the sun, sat the form of a raptor. My first thought was one of the four raven fledglings that constantly explore the air and ground around the refuge headquarters and resident area. But the shape of the head, attentive and looking around, was not that of a raven.

Most of the buteos have a sloped skull that flows into the downward slope of their hooked beak. The bony ridge over the eyes of a buteo gives the profile of their familiar hooded eyes, which can be piercing.

A raven’s skull is shorter and rounder than a buteo’s. Ravens also lack the boney ridge over their eyes, which are like round black buttons. The long and fat raven beak is the key difference. Thick and long, it might be compared to a tapered black banana.

When the bird awkwardly took flight from the ground, white feathers of the short leggings and underwings confirmed that the mystery bird was a buteo, or hawk. What also caught my eye was that its talons were taking a meal for a ride.

Red-tailed hawk

Red-tailed hawk

The hawk flew into a nearby large and ancient cottonwood tree, where it couldn’t seem to find its balance on a branch. As I walked closer, perhaps about a hundred and twenty-five feet away, the bird gave up flapping its wings in amongst the branches and finding a place to perch. It flew down to the ground.

Now quite curious, I retrieved my binoculars out of the travel trailer and walked back to where I was. Scanning the weedy grass and rabbit brush, I could not see any sign of the bird. But occasionally I would hear a sound like a short and high-pitched bark. An odd sound for a raptor!

Walking slowly and carefully through the dried weeds and grass, I chose a direct path towards the sound. After 20 feet of noise with every foot-fall, I stopped and returned to the chunky gravel and decided to try my luck along the edge of the gravel refuge road.

Recalling what I was taught decades ago when learning to track animals, every footstep was slow and light. Any audible sound of the gravel rearranging under my feet was muffled by the strong breeze and moving tree leaves. Keeping my upper body as motionless as possible, I slowly shifted my weight with every carefully-placed footstep. Moving sideways, without moving my head and arms independently was a bit tricky, trying to keep it all a fluid motion. I made a mental note that I needed to get back into Tai Chi to improve my balance and proprioception.

With the binoculars held up to my eyes, I spotted first the raptor head, then the neck. Moving closer, I could monitor the bird’s eyes through the binoculars. Whenever its head and eyes moved in my direction, I froze; sometimes with a foot suspended above the gravel while waiting for the head and eyes to turn away from my direction.

It seemed to take forever for me to approach near where the bird was on the ground. Perched on a large branch lying on the ground and in the shade of the tree was a young hawk. A few features informed me that it was immature. The color of the eyes (iris) were grayish with subtle yellow. Adult Red-tailed hawks have dark brown irises, which often blend in with their black pupils.

The white breast feathers were typical of a red-tailed hawk. However, its white patch was smaller than most others I have seen on juveniles of this species. Below this patch were soft, almost downy variegated feathers; white with wide bands of medium to light brown, and many of them blowing in the breezes sneaking under the canopy of the tree. It’s cere was large and bright yellow, the brightest coloration on this mostly dark bird. Little white showed on the top of the wings and head. Below its white softly feathered leggings betrayed the presence of knobby legs and gray-yellow talon. This bird had not gone through its first molt yet.

Now at about 25 feet from the bird, I didn’t need the binoculars anymore. I held them to my chin to avoid any exaggerated movement. Standing stock still, I studied this bird and wondered why it decided to perch on a grounded branch rather than up in the tree canopy.

Slowly shifting my body a few more feet to the right I was able to see more of the story. One set of talons grasped the wood, and the other…….   All I could see was the bottom of its leg and the upper toes disappearing in the gray-rusty colored fur. These talons were deep into the hindquarters of an unidentified furry mammal with soft gray and tan-orange fur. Below the heap of fur was the bottom of a leg with some white fur and a foot. A paw, to be more exact. With the binoculars, the shape of a paw with dark tan fur had me stumped. Then another feature grabbed my curiosity.

To the right of the hawk I noticed and oddly shaped reddish branch covered with yellowish knobs. It looked like a miniature bloody chainsaw! Not until the hawk picked up its buried talons and shook the heap of fur did I see this odd reddish bar shake as well. It was attached to the heap of fur!

I realized that the hawk was sitting on a hindquarter that was still attached to the bloody spine of a mammal. After shaking the heap of fur and the rib, the hawk looked down at his trapped talons. Apparently the youngster buried those talons into the scavenged meal and was unable to remove them. Shaking it a few times unsuccessfully released it. It finally took a break and glanced around, yawning. And I continued to watch.

After a furious attempt to shake the cumbersome attachment to its talons, it managed to jump up off the fur heap and branch, and turn around with a squeal. Possibly sitting on the rib and powerfully pushing off, its talons were finally dislodged from the fur. With great dexterity, this determined bird caught the entire carnage before it fell on the ground, parked it on the branch, itself carefully perched on the wood, and began to tear off tufts of gray and tan fur. A whitish tail surrounded by gray and tawny-orange fur leads me to guess that the unfortunate meal was a white-tailed jackrabbit, a large relative of the common black-tailed jackrabbit.

The beautiful black and brown banded tail feathers confirmed the age of this bird. Although fledged for a month or so now, it was learning to hunt and feed itself on its own. Finding a partially consumed meal might seem an easy meal for this youngster, but now it needs to learn constraint on digging its talons into prey. And I thanked it for letting me share its experience.

 We need another and a wiser and perhaps a more mystical concept of animals. Remote from universal nature, and living by complicated artifice, man in civilization surveys the creatures through the glass of his knowledge and sees thereby a feather magnified and the whole image in distortion. We patronize them for their incompleteness, for their tragic fate of haven taken form so far below ourselves. And therein we err and greatly err. For the animal shall not be measured by man. In a world older and more complete than ours they move finished and complete, gifted with extensions of the senses we have lost or never attained, living by voices we shall never hear. They are not brethren, they are not underlings; they are other nations, caught with ourselves in the net of life and time, fellow prisoners of the splendor and travail of the earth. –  by Henry Beston, excerpted from The Outermost House

Fuzzy owls day off!

8 Jun

“Some things you miss because they’re so tiny you overlook them. But some things you don’t see because they’re so huge.”
― Robert M. Pirsig, Zen and the Art of Motorcycle Maintenance

The four Great Horned owlets near the Refuge headquarters have fledged from their nest. I visited with the entire family for a few hours the other day as they roosted in two large cottonwood trees. I was privy to some interesting behavior and interactions.

At six to eight weeks old, Great horned owl nestlings will begin to venture from their nest. By climbing branches or other structures next to the nest, the  young begin to exercise and strengthen their leg muscles. They will also flap their wings for the same purpose, often jumping around in the nest while flapping. At this stage, these nestlings, and other large birds of prey, are referred to as ‘flappers’. They will then progress to taking flight for short distances.

The four owl siblings were often spotted flying around inside the fire tower structure, where they could safely exercise without falling to the ground. It was like a large playpen for these owl youngsters. We knew then that they would be fledging soon outside of the fire tower box and take wing.

Owl fledglings remain in close proximity for several weeks.  They will often roost together in the same tree or in neighboring trees. Adults generally roost away from the young, albeit nearby, and they will continue to feed their young with decreasing frequency throughout the summer.

I spotted three of the youngsters with the dad in one tree. The lone sibling was in a tree across the way with mom. I heard the adults communicating with each other shortly before I spotted them, which is how I identified the gender of the adults. A pair of nesting ravens (in a spruce tree ~400 yards from the cottonwoods) tried harassing the lone owlet. Mom had enough and chased them off.

I quietly chuckled while watching the group of three youngsters preen each other while perched on a large tree branch. When one tried preening the feathers on its sibling’s leg, it got a foot of talons in its face. So it stepped on its siblings foot and proceeded to continue preening its leg feathers, while the other tried in vain to pull its leg away. All the while, third sibling did it’s rolling and bobbing the head-thing while watching its two siblings argue about pedicures.

I returned later with the camera and found that the siblings had separated. Two were deep in the shade of the tree canopy, their heads pulled down into their shoulders and wings. They blended in quite well with the rough bark of the tree. One lone sibling was still awake, watching below and in plain view. I set up the tripod and zoomed in for a few portraits. These youngsters still have some downy feathers on their heads, which makes them look lighter than the adults.

As the day was getting warmer and brighter, this one eventually succumbed to nap time. It very slowly tilted to the side and laid prone on a branch next to it.

Unfortunately, a visitor appeared, yelling out, “Whatcha watching there?! Anything good?!” Because it was my day off, and I was not in anything associating me with refuge staff, I told him to be quiet!

This slideshow requires JavaScript.

Choices

23 May

It was my free choice to release all the stuff and trappings in life and live simply where I want. Poor, yet very happy in the natural world. I wouldn’t trade it for anything else.

 

This slideshow requires JavaScript.

On Being an Osprey

15 May

My treat for the day was watching the osprey finally get a fish on its fourth dive into the pond.

I can see its eyes, its talons, it indecisiveness and aborting a dive. I can almost feel it spring out of the water, shaking that cold wetness from its feathered back and wings, climb back up in the air, and finding a thermal to coast, I could almost feel its exhaustion.

I stood there with my eyes projected through the binoculars, almost flying and diving with it, smiling and rooting for this osprey, calling it ‘Sweetheart’, and remembering why it was known as the ‘sea eagle’ where I grew up.

I love ospreys. If I can’t be an osprey, take me with you in flight and in dive.

Osprey at Yellowstone; photo by Jean Philippe Dugault, French nature photographer.

Osprey at Yellowstone; photo by Jean Philippe Dugault, French nature photographer.

%d bloggers like this: