I was recently hiking at the Huron County Nature Center and Wilderness Arboretum in Port Austin, Michigan.  Nice place, but bring the bug spray.

At the far end of the trail system there is a short boardwalk over some swampy ground, and saw this female red-winged blackbird with a mouthful of bugs.

So I stopped to look around a bit more.  Quite soon this male red-winged blackbird showed up and started chattering and displaying his wing feathers.
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So probably by now you've guessed the final photo.  There was a single fledgling in the underbrush.  The male was trying to scare me away, while the female was bringing in a beakload of food.

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I headed off to let them get back to things.

Well, what's to say.  It is a vulture, and honestly looks a fair lot like a turkey.  It's a turkey vulture.

Male common yellowthroats have a bold black mask and sing "whichity whichity which" all day long, and thus are easy to spot and easy to identify.  The female, however, is much more quiet, secretive and in general without field marks besides the coloration of the feathers, legs and bill.  They aren't a bold as the males, but still quite attractive birds when you get a chance to see them.

This yellow warbler was singing away from his perch in a patch of multiflora rose.  One of the most common warblers in the area, these have been seen pretty much every day.

I don't get to see these very often, but Michigan is far enough north to be within the breeding range of the mourning warbler.  This male was foraging in a woodlot but not singing.

This rose-breasted grosbeak was hanging out the shade this morning in Kinde, Michigan.

These are some really common birds, but the largest concentrations of them are at the Great Lakes.  And here is one of them, just sitting on a channel marker on the end of a jetty in Lake Huron.  

Fun fact:  The "double crest" is kind of a mating thing and for most of the year really isn't visible so don't expect to see it too often.  Kind of odd to name a bird after a feature you pretty much never see, but well, then there is the bald eagle named after a feature it does not even possess at all, as it isn't even close to being bald.

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The Cave of Death is not much of a cave, so to speak, but it is a really fascinating hole in the ground nonetheless.  Extending only about 10 feet into the hillside, it ends at a crack too small to continue.  That is, if it were reasonable to continue for other reasons.

Located on the flank of the Poas Volcano in Costa Rica, the Cave of Death just happens to be near some very nice hot springs which have been developed into Recreo Verde.  This fine place was our base camp, actually a fabulous cabin, for our work in this area.

And as for the cave, it is a bit of a tourist attraction, and probably one of the few commercial caves where one does not in fact go in the cave.  Why?  Good question and glad you asked.  The reason for the name is fairly simple, as the cave itself is a huge emitter of nearly pure carbon dioxide.  This, as one might suspect, is what could mildly be called, "bad air" and it is quite dangerous and often fatal to animals that enter the cave.

But, since carbon dioxide is heavier than air, the "bad air" is mostly along the floor, and in fact pools up at the entrance with the spillover rolling out of the cave and along the ground.  How do we know this?  Another good question!  Guy van Rentergem invented a clever little smoker device out of an e-cigarette machine, which could be placed in specific spots to see exactly where the gases were going.  As well, we used a carbon dioxide meter to determine where the gas was and in what concentrations.

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Note that the signs in the photo helpfully say "toxic gas", "entry prohibited" and "don't throw trash".  The last one is kinda funny, compared to the others, until you realize that any trash thrown in the cave is rather hard to retrieve since you can't just go in there and pull it out.

And just to be thorough, we tracked the gas with smoke all the way out of the protective barrier at the cave's entrance where it eventually drifts off in the breeze, while staying right along the ground.
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And while Don McFarlane was taking a number of scientific measurements and recording data and just being an all around science guy...
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It still baffles me as to exactly what he was doing here...

Anyway, one of the more notable features of the cave is the pool of carbon dioxide on the floor, which is remarkably stable, and nearly 100% CO2.  It is just deep enough that any small animals that go in there, end up in that oxygen-free zone and quickly pass out and die.  The Recreo Verde folks told us that the most common animals that die in the cave are rats, snakes and small birds.  And, just looking in we could see at least one fairly recent fatality (sorry, I can't get a species from this photo).
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The smoke was really useful at showing the gas movement out of the cave, but what would it do when placed under the level of the carbon dioxide pool?  Man, you have all the great questions today!  Turns out that the gas has a very slow-moving eddy effect going on, and after a minute or two of watching the smoke it looked like a galaxy was forming.

And just for an added attraction here at Tropicalbats.com, a video about the cave from none other than Guy van Rentergem!  

So that is the Cave of Death, a carbon dioxide-emitting hole that has a penchant for killing small animals.  And now I know you have one more question:  Did any of us actually go in there?  I end with this photo...

***Huge thanks to Recreo Verde for allowing us to study their most interesting little cave.  Awesome place to stay on all accounts and really enjoyed it there.

Every time I post an image of a great blue heron, I say it will be my last.  And then I post another one.  In order to fix this I shall hereby state that this will not be my last great blue heron image, as for some reason I just keep coming up with reasons to post pictures of them.

This most patient bird was on the beach right in front of the Campanario Biological Station.  And it would stand there for long periods of time, while only once catching a fish.  It ate a couple little things it found near the rocks at one point, but it's fish to time ratio was pretty relaxed.

Now what does a person do when they are at the ocean and a larger than average wave comes in?  Toss up their hands and let it go by, right?  Now what does a great blue heron do when they are at the ocean and a larger than average wave comes in?  Here is the answer...

Also on the beach was a spotted sandpiper.  Not sure if it is resident or heading north.

And finally, to end on a colorful note, I ran into this shining honeycreeper down the shore a ways.  Quite stunning birds and must say I didn't do a great job capturing the colors, but what a striking bird to see.

The common pauraque, a bird in the nightjar family related to the whip-poor-will, likes open spaces and nests on the ground.  During the day they don't much fly and are pretty much invisible due to their coloration, but since they are night fliers they do have special eyes.  Which glow bright orange at night when hit with a headlamp, and I easily spotted this female on a nest beside the access road at the Firestone Center.  
Normally they will let you get within 2 to 3 meters before flying off, but when on the nest they just stay put and I was able to get right up next to this one for the photo.  Very attractive birds and not sure I really captured how pretty they are in the pic.