Search This Blog

Loading...

Thursday, February 4, 2016

Bald Eagles fail a second time

In a previous post (DEC 31: Bald Eagles trying for a family-- again), I related that, after failing to breed in the winter of 2014-15, the local pair of Bald Eagles (Pride and his new mate Jewel) began incubating their first egg on or about December 13, 2015. This egg was predicted to hatch 35 days later, around January 17. The adults took turns sitting on the eggs and usually only the tops of their heads were visible above the nest rim. We were very optomistic that this was to be a successful breeding season for the pair. 

Adult deep in nest on January 10:

Bald Eagle nest adult incubating 20160110

Winter in south Florida is normally the peak of the dry season, but the weather has been unusually cool and rainy. On the morning of January 16 we performed a welfare check  and could barely see the nest through the fog. An adult (presumably Jewel) briefly looked down into the nest before again settling down deep. Possibly the eggs were pipping. Once an egg hatches we expect her to position herself a bit higher, "tenting" the hatchling under her wings while continuing to incubate any remaining eggs.

Bald Eagle 0462-20160116

On January 17, a brief but very intense rain and wind storm passed over between 7 and 8 AM. We got out to the Bald Eagle nest around 9:15 AM and found the nest intact but with a recently fallen branch covering its right half. It had not been there the previous day and likely was blown down from the nest tree. The female was deep in the nest and only popped her head up a few times over the left rim of the nest:  

Bald Eagle female after storm 20160117

At about 10:00 AM she stood up, ruffled her feathers, spread her wings and preened for about 5 minutes. She looked down into the nest and then changed her position to face to the right and settled down deep in the nest. No feeding activity or male eagle were observed.

Bald Eagle female on nest 20160117

January 18 was again rainy and cold, with the temperature reaching below 50 degrees (F). We checked the nest but could not see any adult on the nest. Perhaps he or she was sitting very deep to protect an eaglet or eggs from the cold. The next morning (January 19) we visited the nest at about 9:30 AM and watched until 10:10 AM. It was a cool 56 degrees (F) with a brisk northerly wind of about 8-10 MPH. The male (Pride) was standing on the nest. 

Bald Eagle male at nest 20160119

He turned his back to tear at a prey item and clearly was feeding small morsels to one or more eaglets. 

Bald Eagle male feeding nestling 2-20160119

Bald Eagle male feeding nestling 5-20160119

He continued the feeding until 10:00 AM, when he flew to a branch just above and to the right of the nest to clean his bill. His mate was not in sight.

Bald Eagle male cleans bill 20160119

After approximately two minutes Pride flew to another branch which was a bit higher. He seemed restless and was looking about. We thought he might be waiting for his mate (Jewel) to return. He did not vocalize. In the meantine the nest remained uncovered. 

Bald Eagle male moves higher 2-20160119

Bald Eagle male moves higher 3-20160119

Phil, another veteran nest watcher, joined us just after 10:00 AM  and checked the nest again several times that day, reporting that there had been no change-- Pride was still roosting and Jewel had not returned. Later Phil visited at 12:45 PM and reported that now Jewel was roosting on the branch near the nest and that there was no adult on the nest. In view of the cool temperatures this seemed rather unusual, as newly hatched eaglets are incapable of regulating their body temperature and must be covered. Our concern deepened over the next three days after multiple observers failed to see any feeding activity and usually found no adults on or near the nest.

On the morning of January 23, while birding in the wetlands about 1.5 miles southeast of the eagle nest, I saw two adult eagles flying from the nest area in the direction of a large lake where they often forage, about 2 minutes apart at 7:41 and 7:43 AM. It was a cool 62 degrees with a brisk NW wind under threatening skies. Phil reported that the eagles had not appeared back at the nest by 8:30 AM.

Looking back at the entrance gate at sunrise, the red sky promised more rain:


South on Miramar Parkway at sunrise HDR 20160118

Wind stirred the surface of the lake at mid-morning:
    
Late Morning Sky HDR 20160119

Over the next few days it had become quite clear that at least one eaglet had been lost and any others had failed to hatch or were abandoned.  Did the storm and falling branch result in injury to the eaglet or destruction of the eggs? 

My January 29 bird walk took an unusual turn at 7:23 AM when I heard and then spotted Bald Eagles, about 1/4 mile away at the north end of the wetlands preserve. As I moved nearer I could see that there were two adults and a second year juvenile (the latter visible in the upper right corner of this photo, best viewed large): 

Bald Eagle adults and immature 2-20160129

The adults chased the youngster and it flew up and circled, still too far away for good photos. Its dark belly and partially molted flight feathers identify it as a little over 1 year old, in "second year" plumage:  

Bald Eagle immature in flight 4-20160129

The two adults roosted in the grove of herbicide-killed Melaleucas on the far side of the wet prairie. The smaller of the two perched up higher. I took comparable photos from several positions of each from a range of 650 to 400 feet, using the same crop factor so that I could compare their size and shape. This is the male, 400 feet away:

Bald Eagle adult male 3-20160129

The female, at the same range and crop factor, is noticeably larger:

Bald Eagle adult female 3-20160129

At 7:47 AM the female started calling and flew up to roost just behind the male. 

Bald Eagle female joins male on roost 6-20160129

About 10 minutes later the female flew to a higher perch about 100 feet farther along the grove of dead trees, assuming a receptive position. Both eagles kept calling as the male flew and briefly mounted her, but they did not copulate. 

Bald Eagle Jewel flies to perch 3-20160129

BaldEagle Pride flies to Jewel 2-20160129

Because of her distinctive undertail markings I identified the female as Jewel, from the Pembroke Pines nest 1.4 miles to the NW. The male is presumably Pride, her mate, who then quickly flew to a nearby snag and then off to the north. Jewel roosted a while longer before flying up and circling to the north, carrying a small branch. As of today the adults continue to visit the nest site but there has been no sign of any eaglets, which by now would be growing rapidly and require frequent feeding.

Bald Eagle Jewel departs with stick at 0802AM 20160129 20160129


Reflections in the flooded lakeside prairie:

Reflections in flooded prairie HDR 20160131


= = =  = = =  = = = =  = = = = =

Linking to Misty's  CAMERA CRITTERS,

Linking to Eileen's SATURDAY'S CRITTERS,

Linking to GOOD FENCES by Tex (Theresa). 

Linking to SKYWATCH FRIDAY by Yogi, Sylvia and Sandy

Linking to WEEKEND REFLECTIONS by James

Linking to BirdD'Pot by Anni

Linking to Wild Bird Wednesday by Stewart

Linking to I Heart Macro by Laura

________________________________________________

Please visit the links to all these memes to see some excellent photos on display


________________________________________________

Thursday, January 28, 2016

Palm Warblers and Alligator Flags

Morning clouds reflect on the surface of the lake in the local wetlands:

Looking NW before sunrise HDR 20151030

The Palm Warbler is one of the most common bird species seen on residential lawns during Florida's winter. Our visitors belong to the drab western subspecies, which breed in central and western Canada and winter in Florida and the Caribbean.

The Palm Warbler's long legs are an adaptation to its habit of foraging on the ground:

Palm Warbler 20131114




Palm Warbler 2-20151009


 
This Palm Warbler has caught a very large grub:
 
 Palm Warbler (Dendroica palmarum) with worm 20120219

Another poses nicely for me:

Palm Warbler 2-20150212

In spring, its plumage brightens up...
 
Palm Warbler 20140331

...but never reaches the intensity of this Eastern (Yellow) Palm Warbler subspecies which breeds in eastern Canada and crosses over to winter in Mexico by way of Texas (May 15, 2014 in Illinois):

Palm Warbler eastern 2-20140504


This is another example of the eastern subspecies, also photographed in Illinois (May 1, 2012):

Palm Warbler 20120501

A group of small and active birds caught my attention as I was exploring the near shore of the lake in our local wetlands. Bright  yellow at the base of their wagging tails identified them as Palm Warblers. Five or six were gathered on what looked like a collection of slender weeds. They were exploring inconspicuous red flowers that draped down from the tips of the stalks. This led me into a deeper inquiry about this behavior.

Palm Warbler and Alligator Flag flowers 20151121

Enjoying the aesthetics of the scene, I took several photos. I learned that these flowers are very attractive to flying insects, drawing in the Palm Warblers.

Palm Warbler and Alligator Flag flowers 2-20151121

The flowers sprang up from a clump of broad-leafed plants that I recognized as Alligator Flag:

 Alligator Flag in bloom HDR 20151120

South Florida experiences a wet season (March-Oct) and a dry season (November-February). In response to seasonal variation in rainfall, vegetation in the Florida Everglades has evolved to take advantage of several micro-habitats. Almost all are related to the hydroperiod, or the average amount of time a plant stands in water over the year. Sawgrass, the predominant plant in the extensive marshes thrives in a hydroperiod of about 9 months. It can survive shallow flooding all year around, but will die if deeper water keeps oxygen from reaching its roots.

This was a stand of Sawgrass in our local wetlands back when the restoration area was actively managed by controlling water levels and removing exotic invasive plants.  In the background is the skeleton of an ancient cypress that once stood in the historic Everglades. Sadly, now that this area is to be turned into a reservoir, all restoration efforts have been abandoned and this spot is now totally overrun by shrubs and trees.

SawgrassRecovering

"Wet prairies" of grasses, rushes and sedges develop in slightly elevated areas where shallow water may cover the ground only about 3 to 7 months of the year. This is a fair example of a restored wet prairie, still actively managed, adjacent to the planned water impoundment:

 Wet prairie HDR 20151027

Alligator Flag must be waterlogged all year round, so it is found in the deeper channels (sloughs or "slews") that cut through the marshes and prairies. American Alligators dig out ponds of open water which sustain mammals, birds, turtles, fish and other organisms all through the year, assuring these large reptiles with a reliable food source. 


A bit to the north, an alligator has carved a circular pond in the wet prairie. Sedges are thriving at its margin:

 Pembroke Pines WCA 2-20130117

An American Alligator basks next to its pond during the dry season:

Alligator 20130202


Alligator Flag (Thalia geniculata) requires water all year, and is so named because its presence in the open Everglades suggests the presence of an alligator "hole." Its flowers are obviously attractive to flying insects which in turn attracted the small flock of foraging warblers.

I found a fascinating blog about Alligator Flag (Alligator Flag is a Snappy Wildflower)
which in some detail describes the "rat-trap pollination" that occurs when a bee enters the flower and triggers a mechanism which simultaneously collects pollen from the intruder and deposits its own pollen, as it forcibly ejects the insect, thus assuring cross-pollination and also closing the entrance to the flower. (Read the blog, as I have grossly oversimplified the process.)


My macro for the week is this White Peacock on the flower of a Balsam Pear:

White Peacock on Balsam Pear 20151112


= = =  = = =  = = = =  = = = = =

Linking to Misty's  CAMERA CRITTERS,

Linking to Eileen's SATURDAY'S CRITTERS,

Linking to GOOD FENCES by Tex (Theresa). 

Linking to SKYWATCH FRIDAY by Yogi, Sylvia and Sandy

Linking to WEEKEND REFLECTIONS by James

Linking to BirdD'Pot by Anni

Linking to Wild Bird Wednesday by Stewart

Linking to I Heart Macro by Laura

________________________________________________

Please visit the links to all these memes to see some excellent photos on display
________________________________________________