HDR

I've been working on a different type of photography called "High Dynamic Range", or HDR photography. The idea is to take multiple pictures of the same image, all at different exposures that will allow for all detail in the highlights and the shadows to be recorded. In a normal photograph, although not ideal, usually some of the details in the shadows or highlights have to be clipped (ignored) to allow for proper exposure of the subject. With HDR photography, all details are recorded, so it's up to the photographer in the post processing to decide how he/she wants the image to look. It takes a lot more work to photograph a subject in HDR (9-12 different exposures to make just one image) and a lot more equipment (a tripod, a cable release or timer release, and a special software program), and a VERY still subject (people are not always the best subjects for this type of photography, but if you can convince your human subject to stand very very still for about three minutes, it can work fine), a lot more processing time (it's taken my new computer up to 30 minutes to process a 12 image series), but I think the results are really worth all the extra effort.

Need to be convinced? Here are some recent examples from our trip to Bluestem Prairie.

My Dad, the ecologist:



A sunset:



The prairie:



A wild sunflower among the Bluestem:



The open road as we traveled from location to location on our field trip:



A beautiful farm in western Minnesota:



And probably one of my favorites from the weekend, my husband and son, fishing on Lake LeHommedieu in Alexandria, MN:



I think I'd like to try some macro photography using this technique, but I need a day without any wind. Wind kills macro photography using standard techniques, but when trying to use HDR techniques, it makes it almost impossible.

The photographer at work:

Thanks for looking. Note: for best viewing, click on each photo to enlarge and sharpen it (true for all photos posted actually).

Here there be dragons

In this case, these are good dragons that eat many of those annoying mosquitoes over their several-month lifetime. Damselflies and dragonflies belong to a group of insects (Odonata) that are relatively ancient, and their preserved fossil forms from 300 million years ago look much the same as their descendents do today.

Two sets of wings (which can be operated independently of one another) gives them both speed and maneuverability, and like hummingbirds, dragonflies can fly forwards (at 100 body lengths per sec), backwards (3 body lengths per sec), and hover in place. They can dart out from a perch to catch small flying insects at speeds of 60 mph. Like birds, some dragonflies may hunt from a perch, turning their heads to follow potential prey then darting out to catch them, and returning to the perch to consume them. Other species primarily hunt from the air, cruising back and forth across the wetland to chase down those pesky mosquitos.

The most common species I've seen in suburban wetlands are these:

This is a male 12-spotted Skimmer (aptly named), which is easily recognizable from a distance because the white spots contrast sharply with the dark ones. Only males have the bright blue abdomen (females are duller in color). Skimmers perch horizontally while hunting, which enables amateur photographers to get good pictures of them, even though they are only 2 inches long.

This is a Widow Skimmer which hunts from the tips of weeds in open fields, rather than over the water like its 12-spotted cousin. Males defend small territories, but establish new ones each day, which I'm sure adds to their energetic cost of life.

This is a White-faced Meadowhawk, a small (1 inch) dragonfly common in the low vegetation where it perches to hunt. Being so small, they are vulnerable to predation by insectivorous birds, and therefore don't let you get close enough to get a good photo of them. For better pictures of meadowhawks, see photos of another St. Paul-ite at http://ecobirder.blogspot.com/2008/10/carpenter-dragonflies.html

And lastly, a small (1.5 inch) but very distinctive dragonfly that I only saw once out in a prarie field, the Halloween Pennant, so named because of the black and orange markings on the wings. As you can see in the photo, they hunt from the tips of flower or grass stalks.

Some interesting facts about dragonflies:
They spend most of their life in water growing to adult size; they molt (shed skin) 8-17 times, increasing in size with each molt. In northern climates, they may live 8 years as a nymph, but only one summer season as an adult.

The enlarged and clawed lower lip of dragonfly nymphs can shoot out in 1/100 of a second as far as 1/3 of their body length to snare small crustacean prey. In the absence of fish, they are the dominant predator in ponds.

The gills of aquatic dragonfly nymphs are located inside their rectum; they breathe by moving water rapidly in and out of the anus (note: fresh water turtles do this too).

One mating provides a female with enough sperm for her reproductive lifetime. Although mating events may last hours, the transfer of sperm to the female only takes a second. The rest of the time the male is most likely removing the sperm from any previous mating; his penis is highly modified with a brush that scoops up any sperm and ejects it.

Dragonflies have really beautiful, multifaceted eyes that are particularly
good at picking up motion.

To see some really nice HD photos, go here:

To see a slow-motion video of Dragonfly flight (from David Attenborough's "Life in the Undergrowth"), go here:

Japanese beetles -- Round 2

At first I thought they were pretty, now I hate them. When the Japanese beetles graduated from eating raspberry leaves to eating the fruit, I was willing to give some of it up because we had a bumper crop. But then they moved onto the roses. They especially love the white, pink, or yellow large-flowered hybrid tea roses, on which they seem to conduct mating orgies that involve devouring the entire rose.

I take my revenge by cutting the flower head and quickly submersing it (and the mass of beetles) in a container of soapy water to watch them drown. Soap seems to dissolve whatever cuticle lipids they have that allow them to float to safety. Soapy water kills them - yea! But, looking more closely I found that some sank immediately and others floated up at the boundary of the soapy foam. Why the disparity? What made some sink? Any ideas to explain the difference?

The birch trees are losing a lot of their top leaves to Japanese beetles as well. If you've noticed brown skeletal remains of leaves around your trees this summer, it's probably due to a JB infestation.

We need a very cold winter with no snow cover to kill off the larvae that will be developing in our lawns. I never thought I would wish for that!

It's not a hawk, it's not an eagle --

It's an osprey, and although it looks like a small bald eagle, it is not really closely related to them.  In fact, there is only one species of osprey, distributed world-wide, and it is so different from hawks, falcons, eagles, and owls, that it is classified in its own family.



It's becoming more common to find ospreys nesting in parks, and this pair took up residence in a ball/soccer park in Maple Grove.  Similarly, an osprey nest at the Roseville ballfields made the local newspaper because the birds were so cooperative in posing for photographers. The lights make a perfect nesting platform, once a few sticks have been added.  The female lays two to four eggs and incubates them for 40 days (a long boring stretch of sitting in the hot sun).  The number of young raised depends on how many fish the parents can catch.





Males take care of most of the feeding and make frequent deliveries of fish to the chicks for about 6 to 8 weeks.  Osprey chicks are especially vulnerable to predation from Great Horned Owls and Racoons, so the female usually stays close to the nestlings.



Sometimes, it only takes one foot to grab and immobilize the fish, like this bird is doing here.



Osprey have remarkable feet, as well as wonderful eyesight, to help them catch fish feeding near the lake surface.  Like owls they can rotate their outer toe backward to oppose the other two, giving them a two prong pincer to immobilize their prey.  In addition, they have rough, barbed scales on the bottoms of their feet that help grip and stabilize that wriggling, squirmy, slimy fish.



Six weeks after hatching, young osprey like this little guy above, look like miniatures of their parents, but are not yet ready to catch fish on their own.  They might leave the nest and undertake short flapping flights to the nearest tree, but are still probably fed largely by the adults.





Seeing free-flying birds like this in a semi-urban area is a thrill.  Like the Bald Eagle, osprey almost disappeared from North America in the 1960s due to contamination of the water and their fish prey with DDT and related pesticides as well as PCBs used in plastics manufacture.  Vigorous reintroduction programs begun in the 80s and 90s (in MN) helped re-establish breeding pairs in the state.  Since osprey mate for life and offspring return to the area where they were raised, the Minnesota osprey population seems to be a healthy one again.

Hawks We Have Seen

The other day I was out looking for dragonflies when I saw this beauty in the tree just above me.  She (I think it was a she because it was a BIG bird) was sitting at the edge of a grassy old field full of wildflowers, scanning for mice or snakes or frogs or whatever appealed to her at the moment.  And she was completely oblivious to my creeping up on her to take her picture. 



This is an adult Red-tailed Hawk (you can tell by the red tail -- duh).  This species is one of my favorites.  Years ago I published (an interesting, I thought) paper about them, comparing their daily energy budget with that of their temporal counterpart, the Great Horned Owl.  Both species are common and are year-round residents all over North America, meaning they stick around throughout the nasty winter as well.  Unlike the owls, however, Red-tailed Hawks will lower their body temperatures at night during the winter when they run short of food and have failed to eat for several days.  This mild hypothermia allows them to balance their energy budget.  Perhaps being a nocturnal hunter allows owls to have greater hunting success, because their body temperature is absolutely stable at very cold temperatures, even when they are food-deprived.  Like humans, the feet and the head are two key areas of heat loss in hawks.  Both areas are well insulated by feathers in owls -- that might make a difference in the cold.  Check out those sharp talons in this picture (click on it to enlarge).  Could anything escape these pinchers?

Like many birds of prey, these hawks enjoy really superb binocular, color vision that enables them to pick out the tiniest moving objects in complex backgrounds.  In addition, they have two different fovea (focus spots) in their retinas, one in the back of the eye like us, and one near the top of the eye, which allows them to focus on objects below.  I finally got too close to this bird, and she began to focus on me, as you can see here.  She sort of looks cross-eyed.

The Gold in my Garden

The wildflowers in the backyard are stunningly colorful right now: red, yellows of various sorts, purple, pink, lavender, greens of all sorts. Even the weeds are pretty. The colors or the smells or both are attracting a wide variety of insects and birds, especially one. Do you see him peering out between the coneflowers? (Hint: he's bright yellow and black). Yup, it's the American Goldfinch, also known as the Eastern Goldfinch or Wild Canary.

This is the breeding plumage of the male. He will drop these colorful feathers to look much more like the drabber and far less yellow female during the winter, when Goldfinches get together in large flocks to scour the countryside for seeds. But you can still recognize them by their striking black and white wing patches. You can tell how small these little finches are by comparing him with the size of the coneflower. They only weigh about 12-15 grams (roughly the equivalent of a McDonald's ketchup package).



After feasting on the seeds just beginning to form in the Blazing Star outside my kitchen windows, the Goldfinches have moved on to the very tall Cup Plant on the border of the wildflower garden. They tug and pull at the innards of those flowers like they are trying to dismember them, and bend the flowers by hanging upside down on the ends of the stems to reach inside.

The camera is almost unable to distinguish their yellow color from that of the flowers.

Life is great for Goldfinches now, but in a couple of months when the temperatures dip below freezing and the daylight decreases to a bare 8 hr per day, Goldfinches will remain in MN, unlike many of our summer bird species. Even though they are quite small, Goldfinches are veritable furnaces of heat production. They can maintain a warm and constant body temperature, even at -40 F overnight! That's the advantage of eating seeds, which provide a fat and protein-rich diet. Even nuthatches and chickadees, which eat insects during the summer, switch to eating seeds at your bird feeders during the winter. By foraging in large flocks during the winter, Goldfinches take advantage of the "many eyes" strategy to find new food sources while watching out for potential predators.

in the Austin, Texas backyard

This week we have experienced the great Texas heat wave up close and personal. They are working on a record 42 straight days of > 100 F temps, which make it really hard to want to go outdoors. But we did venture out one night, when the already excessive air temperature was added to by the re-radiation from the concrete and steel of the downtown buildings. Why did we subject ourselves to this? To see the emergence of 1.5 million Mexican free-tailed bats at sunset from the Congress Street bridge. This daily occurence is quite famous, and draws hundreds of people each night that line up on and below the bridge to watch.

Minute cracks in the underside of the bridge are the perfect size for these bats to climb (or fly) in and create their communal roosts. They arrive here (from the south) in March, and breed and raise young, migrating south again in September. I assume the moisture along the cracks is due to bat excreta.

We walked along the river while waiting for the bats to emerge on their foraging flight, and I found a dead one on the sidewalk. You can clearly see the free tail; the tail of other bat species lies within the membrane that runs between their hind legs.

At last, just as predicted by the local news and hoteliers, the bats began to emerge from the far end of the bridge across the river, and then in successive waves from each of the slots along the underside of the bridge. They flew in a straight line down-river, with the entire emergence probably taking about 15-20 minutes.

According to Wikipedia, this mob consumes 10,000 to 30,000 pounds of insects EACH night.
After this excitement, we had to retreat to a hotel and drink about a gallon of water to rehydrate. I can't imagine what the air quality inside those roosts is like with a million and a half hot little bats heating up the enclosed space and producing great quantities of ammonia as they digest their evening meals.

Hooray For Hoverflies

I was sitting out in my garden with my daughter this morning, watching her enjoy the flowers, when suddenly, she ran away screaming. I asked her what had happened, and the best I could get out of my two year old was, "Scary Bee!" I happen to love trying to photograph bees, because I think they are lovely and such interesting insects. I love trying to capture their amazing eyes and all the pollen on their legs, so I grabbed my camera and my macro lens (although, I'm lacking a tripod at the moment - and that would have helped immensely). As I got closer to her "scary bee", I noted that it was not a bee that she had seen but one of the very friendly and helpful Hoverflies that inhabit my garden. I can see why she was confused - upon closer inspection they look quite a lot alike - although the Hoverfly is quite a lot smaller and hovers above the flowers whereas the bees simply buzz around.

(Click pictures to view them larger)







Then, as I was photographing this first one, another one landed on the flower next to him. At first, I thought it was actually a bee, because he was the same size as a bee, but I later learned that bees and wasps all have two sets of wings and flies only have one - so this is just a different species of hoverfly. Notice how much bigger he is compared to the brown part of the flower than the first guy? He's significantly bigger - and much easier to photograph. He also didn't hover the way the smaller fly did - and I have been told it's because hovering requires large amounts of energy and therefore cost prohibitive for such a large fly.







And one last one, because I love all the pollen stuck to his rear end:



What I love most about these syrphid flies (and probably what most farmers love most about them as well), is that although the adults eat mostly pollen and nectar, the syrphid maggots eat lots of other things that we consider pests - like aphids. Have a problem with aphids destroying your garden? Plant some plants that attract hoverflies nearby:  alyssum, Iberis umbellata, statice, buckwheat, chamomile, parsley, and yarrow.

Despite how much they may resemble honeybee or wasps, hoverflies don't have a stinger and pose no risk to humans at all. So, if you, like my daughter, flee at the sight of anything black and yellow, take a closer look and enjoy watching this busy little insect pollinate your garden.

If you want more information on the subject, it just so happens that my sister did her Ph.D. thesis on the the Syrphid Flies, so I'm sure she would be happy to post a link to her research.

They're baaaack....

Many of us have reported seeing turkey hens and babies in the backyard the past couple of weeks.  This is a welcome sight because turkeys became extinct in Minnesota in the 1880s, probably due to over-hunting and loss of habitat and food supply as more people settled in the midwest.

How did they make a comeback?  In the 1970s Minnesota DNR traded walleye, prairie chickens, ruffed grouse, and hungarian partridge (an introduced species) to Missouri and neighboring states for wild turkeys, allowing them to get re-established in woods and fields far from agriculture.  Apparently the climate agreed with them, or at least they tolerated the frigid, snowy winters and the tropical monsoon summers to thrive well enough to allow their population to increase markedly.  Now there is both a fall and spring hunting season on them in MN, and I know some Minnesotans brag about the great taste of a wild turkey at Thanksgiving.



In April this year, a handsome Tom and his three lady friends visited the bird feeders in my backyard, picking up the leftovers the birds and squirrels had missed.  We saw them a couple of times this spring, but it was a long time before we saw them again in early July when a herd of females marched across the backyard on their way to the woods.  Last week, two hens brought their new and not-so-new chicks through the backyard to feast on the insects in and around the wildflower garden.  They were too shy of me trying to take their picture to pose nicely and made a beeline for the deep woods at the back of the yard.



I could only see 6 or 7 chicks, of two different ages in this bunch, and since Turkeys lay about 8-10 eggs in their ground nest, a lot of the babies must have been gobbled up by foxes, raccoons, or possums.  Baby turkeys, like chicks, are precocial, which means that they can run almost immediately after hatching, quite unlike the baby robins which are like limp noodles for the first 4-5 days of their life.  They can also feed themselves, which makes the hen's job mostly protection.  This is probably also the reason that hen turkeys raise their young together, forming flocks of up to 30 birds of varying ages in the midsummer.



Turkeys eat  a variety of insects, seeds, and young, rapidly growing weedy plants through the spring and summer, so they are a help to your garden in getting rid of weeds and pests.  In the fall their diet switches to nut crops, like acorns, which allows them to put on a thick layer of fat to help them survive winter cold.

Turkeys CAN fly, even though Toms may weigh up to 20 pounds!  In fact, with those powerful breast muscles (that we like to eat) they can zoom over tree tops at 55 mph. They roost at night in trees, which keeps them safe from the nocturnal ground predators.

Butterfly afternoon

Torrential rain has kept me indoors most of the time for the past two days, but the sun came out this afternoon, and I noticed that the milkweed was chock-a-block with insects swarming the blossoms. They were probably overfull of watery nectar after all that rain. Along with the usual complement of wasps, small bees, and monarch caterpillars, four species of butterflies were foraging intensively, and there were several individuals of each.

The Monarch butterflies were bossy and kept chasing the others away, but with four bushy clumps of milkweed plants, they couldn't exclude all the other foragers.



The Swallowtails were back, but only a single individual at a time.

Two new species appeared in the mix, and I had to look them up to be sure who they were. Here's a good website to do that. http://www.butterfliesandmoths.org/ . Go to the Image Gallery if you just want to compare pictures with what you see outdoors.

This is a Red-spotted Purple (I've never seen one of these before). Handsome, isn't it?

And this is a Red Admiral (they are pretty common), and I found them on the Coneflowers and the Blazing Star today also.

The Red Admiral was very cooperative and let me take a lot of pictures of its bizarre facial features. Check out those ropey antennae with the bullbs on the end and his funny-looking face in this profile. His eyes look like they have slits, instead of the usual compound facets. That yellow thing coming out of what looks like his turned up nose is the proboscis that it stuck down into the flower to slurp up the nectar. You can see a few of the milkweed's yellow pollen sacs stuck to his legs.

A beautiful afternoon for butterflies.

(P.S. If you click on the image, you'll get an enlarged view.)