Sunday, August 18, 2013

South Florida birding hazard

The weather eased up a bit before we returned to Illinois. This may have been partly due to the haze produced by dust that traveled 6,000 miles across the Atlantic from Africa's Sahara Desert. The dust arrives annually to south Florida in early summer and persists until autumn, when the tropical waves from Africa begin to deliver hurricanes. The dust cloud is believed to suppress cloud formation and is also blamed for an adverse effect on the coral in the eastern Atlantic, but is not known to harm humans.  

According to NASA, Saharan dust is made up of a mix of minerals including clay and iron, as well as organic material such as pollen and micro-organisms. It travels across the Atlantic at about 5,000 feet above the ocean and sometimes crosses the Gulf of Mexico all the way to the Texas coast.  See NASA's 2013 Hurricane Mission to Delve into Saharan Dust 

The amount of dust varies from year to year and can produce very colorful sunrises and sunsets. Last year our early morning skies turned bright pink, and I also witnessed an unusual "mirrored sunrise" directly west of the actual sunrise. See my blog that has photos of these events: Egrets under pink skies.

On August 4, minutes after a golden sunrise, I took this photo of the sky, looking west over the wetlands preserve next to our home. This viewpoint is almost the exact spot from which I witnessed last year's "mirrored sunrise." 

Harbour Lake looking west at sunrise HDR  20130804

Falling water levels isolated a patch of water from the lake. The surface of the water rippled as small fish struggled to gape air. I frightened several herons that were feeding there. The soft morning light imparted a gentle glow that enhanced the stark white plumage of an adult Black-crowned Night-Heron as it alighted atop a shrub.

Black-crowned Night-Heron 20130807

The heron had piercing red eyes.

Black-crowned Night-Heron 2-20130807

Two Green Herons flew up from the area. An adult bird with solid rufous neck feathers is on the right, while a streaked immature is opposite it.

Green Herons 20130803 

A juvenile Red-shouldered Hawk occupied the top of a power pole.

Red-shouldered Hawk juvenile 3-20130803

On the gravel road, a pair of Common Ground-Doves looked for breakfast.

Common Ground-Doves 20130804

Ground-doves can be quite wary. I was lucky to get fairly close to this male who lingered on the path after his mate and one young bird flew into a nearby tree.

Common Ground-Dove 20130805

Although the birding was not particularly good that morning, on my way back home I stopped again to snap a photo of the clouds from a muddy trail on a berm that covers a stormwater culvert leading out into the lake. The sky had a pink cast but the color did not show up well. I would not have posted this photo except for what I did NOT see. If you click on the photo you will see a larger image with a box in the lower edge of the image that shows where a poisonous Cottonmouth moccasin was hiding.

Harbour Lakes dock looking west 20130804

I did not notice the snake until I took a couple of steps forward. That was when I caught the movement of its white gape in my peripheral vision. It was so well obscured by the sedge and grass stems that I would not have seen it at all. Note the triangular head, black mask and elliptical pupils. Like all poisonous pit vipers, it has a heat-sensing pit between its eye and nostril. 

Cottonmouth closeup 2-20130804

Not planning to walk in high grass, I did not wear my snake boots that morning. The Cottonmouth  was a good three feet away with most of its body in the water but it did coil and threaten when I maneuvered around to get a better photo. Then it bolted and swam away. 

Cottonmouth 20130804

It was a medium size, about 3-4 feet long. Characteristically, it swam with its head held above the water, unlike harmless water snakes. After this I started noticing every crooked branch or any curved shadow! 

Cottonmouth retreating 2-20130804

Later that afternoon, from the safety of my back patio, I enjoyed visits from a few long-legged waders, including a flock of White Ibises.

White Ibises 20130803

I could not get a full-body shot of this Little Blue Heron before it bolted.

Little Blue Heron thru window 20130802

This female Anhinga was an interesting visitor. She threatened me when I approached to take her picture, and engaged in a threat display before a grudging departure.

Anhinga 20130803

Here is a brief clip of the Anhinga's display. If it does not show up, try this link: http://www.youtube.com/watch?v=4G62BcJ_B8c&feature=youtu.be





14 comments:

  1. yeah, we get the water moccasins here, too. along with the copperheads. LOVE the night-heron shots! wow!

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  2. Wonderful birds! The snake is quite beautiful too. I'm glad you saw it before you steped on it.

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  3. Awesome birds and a lovely sky! The snake is a cool sighting but scary too. Wonderful photos, Ken!

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  4. Beautiful photos! The sunrise photos are especially wonderful.

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  5. Learned a lot (didn't know those dust storms reached all the way to Florida, didn't know poisonous snakes swim with their heads up).... enlarging that snake photo made me jump just to think about almost stepping on it!

    Really enjoyed seeing beautiful Florida when we're not there. summer looks pretty darn wonderful in spite of the dust. (I'm wondering now if it gets to SW Florida, where we hang out.)

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  6. Glad you saw that snake in time! The night heron shots are beautiful. Love the Anhinga threat display.

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  7. Great post!! Boom & Gary of The Vermilon River, Canada.

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  8. Very interesting that the dust comes all that way from Africa. It certainly creates some beautiful colors in the sky and on the wildlife. The threat display from the Anhinga is amazing.

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  9. I was going really well perusing all your beauties, 'til the snake arrived. I about had a heart attack!!

    I did not know that about the dust 'til today. Did you know that Sahara means desert in English?

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  10. SHALL I JUST SAY, GORGEOUS, OUTSTANDING, BRILLIANT AND STUNNING, ALL IN THE SAME BREATH :)

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  11. Gorgeous photos! I love the crispness of the black-crowned night heron images. Contrasts nicely with the soft, beautiful light in your sunset images.

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  12. Great shots of your "dusty" skies!
    Watch your step in that grass! Yikes! Still, they have their own beauty, don't they?
    Gotta love those laser-beam eyes of the night heron.

    Very nice series, Ken!

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  13. Great shots and I sure didn't know anything about Saharan dust- thanks for sharing that, very interesting. Cottonmouths- we got plenty here...horrible creatures!

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