Thursday, September 26, 2019

The Bald Eagles are back

The local Bald Eagles which nest in nearby Pembroke Pines, Florida have returned to begin a new breeding season. Ground observers have tracked their activities ever since the nest was discovered back in 2008. Last season they raised two eaglets. During the summer we often saw the adults flying over the local wetlands from the area of the nest to a large lake in our subdivision, usually early in the morning.

On July 16, both members of the pair flew together just before sunrise. this is the female, distinguished by her larger size:

Bald Eagle female 20190716

This was the male on July 16:

Bald Eagle male 20190716

The female flew low overhead on August 13:

Bald Eagle 01-20190813

Here is the male on August 26:

Bald Eagle 02-20190826

During the summer the eagles have been sighted resting atop of this lighthouse on the island in the biggest lake in our Sunset Lakes subdivision, which is about 2 miles southeast of the nest (click on photo for better view):

 Lighthouse Island HDR 20150216

The "official" breeding season begins on October 1, about three months earlier than in the northern reaches of the eagles' range. Both members of the pair were present at the nest on September 14, 2019. The female (Jewel) was roosting on a branch just a few yards east of the nest...

Bald Eagle female Jewel 06-20190914

Bald Eagle female Jewel portrait 04-20190914

...while the male (Pride) was mostly hidden as he roosted just to the right of the nest. Note that fresh green branches have been added:

Bald Eagle male at nest 20190914

On September 21, the pair were busy at restoring the nest, or "nestoration." The male (to the left) continuously brought in sticks, while the female kept watch and adjusted their placement:

 Bald Eagle pair nestoration 01-20190921

Bald Eagle pair nestoration 02-20190921

Off goes the male to find more sticks. In flight, he often breaks them off from dead trees: 

Bald Eagle pair nestoration 09-20190921

Following is a review of their prior (2018-2019) breeding season. Pride is the original male who was first seen at this nest site in 2007. Since breeding age is 5 years, he is now at least 17 years old. Jewel is his second mate. His first mate (Joy), disappeared in late October, 2014 after hatching 13 eaglets in 7 broods, of which 11 successfully fledged. She was quickly replaced by a 4 year old female (Jewel) who did not breed in 2014-2015. 

Then, in 2015-2016 Jewel lost her first nest and its only eaglet in a storm. Bald Eagles occasionally nest a second time if they lose eggs or a brood early in the season. That year, because of widespread storms, this occurred with several pairs around Florida. Jewel indeed nested a second time. To date, her 5 attempts have produced 9 known young, 6 of which survived to fly free.

Here is the pair last season, roosting in a tree near the nest on October 7, 2018. The male (Pride) is to the left, while his mate (Jewel) is perched higher up. Note that the male's smaller body is more tapered towards the tail end while Jewel is much more filled out "below the waist:"

Bald Eagles - Pride and Jewel 01-20181007

The pair spent much time preening:

Bald Eagle female Jewel 01-20181007

Bald Eagle male Pride 01-20181007

When Pride finished preening he got all ruffled up:

Bald Eagle male Pride ruffled 05-20181007

Bald Eagle male Pride ruffled 06-20181007

A closeup of Jewel's talons shows the elongated hind toe (hallux), characteristic of the female:

Bald Eagle female Jewel talons 05-20181007

Jewel is checking out something on the ground below:

Bald Eagle female Jewel 04-20181007

The nest appeared to have some new sticks added:

Bald Eagle nest 20181007

The pair worked on the nest into mid-November, and courtship activity increased. On November 17, 2018 they copulated successfully.

Bald Eagles Jewel and Pride 05-20181117

Bald Eagles Jewel and Pride 09-20181117

Eagles Pride and Jewel matiing 03-20181117

Their first egg was laid about December 5, and it hatched around January 10, 2019.* Two eaglets were first seen on January 31, 2019:

Bald Eagle eaglet 1046AM 20190131

Bald Eagle both eaglets and Jewel 1041 AM 20190131

The first egg to hatch is more often a female, with a chance of about 2 out of 3. Here are the two eaglets, from left to right, the male (P Piney 22) and female (P Piney 21) at about 11 weeks of age, on March 16, 2019:

Bald Eaglets male and female P Piney 22 and 21 03-20190316  

Both  fledged on successive days just one week later. They immediately returned to the nest to be fed:

Bald Eaglets male flapping  03-20190403

Bald Eaglets female and male 02-20190403

There was a chaotic food drop on April 14, when  the male parent flew in with unidentified prey, but both eaglets attacked fiercely, driving the adult back:

Chaotic prey drop 06-20190414

Chaotic prey drop 01-20190414

Chaotic prey drop 04-20190414

The older eaglet then crouched down over the prey and spread her wings to guard it while the younger eaglet settled down behind her:

Chaotic prey drop 07-20190414

By mid-May, both youngsters had migrated away, probably to find cooler water to the north, where fish tend to be nearer the surface and are easier to catch.

As of this writing, in September, 2019, the occupants of this nest of eagles is known to have hatched out at least 22 chicks, of which 17 were confirmed to have fledged successfully. Although we hope all 17 are still alive, the sad fact is that as few as 50% of the Bald Eagles which leave the nest survive into adulthood. 

Research shows great variation in survival rates. The proliferation of Florida's eagle population suggests that conditions may be more favorable here. However, when the eagles move into urban areas they are subject to new hazards, particularly motor vehicle collisions and injury from power lines. Aggression between eagles over territories and mates also may become more common where they compete for limited resources. Most mortality occurs within the first few months before the eaglets gain survival skills.

A spreadsheet (PDF) which details observations of this nest since 2008 may be accessed AT THIS LINK

*In estimating the timing of the laying of eggs and hatching of the eaglets, we must depend upon clues from changes in the behavior of the adults. The onset of incubation coincides with the laying of the first egg, which is when we suddenly see one of the pair down deep and immobile in the nest. Hatching is a time of excitement, as the parents shift position frequently, peer down into the nest, and they start bringing in prey and tearing off bits to feed the tiny chick. The adults also sit a bit higher in the nest after the first egg hatches, supporting themselves on their wings to form a "tent" to shelter the chick and yet provide warmth to any eggs that have not yet hatched. 

Volunteer nest observers share their sightings and photos, and respond to queries in the Pembroke Pines Eagle Nest Watch FORUM here, which includes a link to spreadsheets that document observations over the past three breeding seasons . 

= = =  = = =  = = = =  = = = = =

Linking to Misty's  CAMERA CRITTERS,

Linking to Eileen's SATURDAY'S CRITTERS,

Linking to SKYWATCH FRIDAY by Yogi, Sylvia and Sandy


Linking to BirdD'Pot by Anni

Linking to Our World Tuesday by Lady Fi

Linking to Wild Bird Wednesday by Stewart

Linking to Wordless Wednesday (on Tuesday) by NC Sue

Linking to ALL SEASONS by Jesh


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


Thursday, September 19, 2019

Countdown to the equinox (#877)

In our local south Florida birding patch, land-bird migration usually peaks in October. I have seen 22 warbler species here during fall migration, of which 11 species have persisted into the winter months. Among them were these early arrivals--

Black-and-White Warblers breed just to the north and are commonly present by August. They creep along the trunks and major branches, mouse-like. The fall male Black-and-White Warbler has a dark face patch:

Black-and-White Warbler male 01-20190817

In spring the male is more densely streaked and may have an entirely black chest (April 14, 2019):

Black-and-White Warbler 05-20180414

Females and first year males have pale faces:

Black-and-White Warbler 05-20190911

They are very acrobatic as they seek insect prey hidden in the bark:

Black-and-White Warbler female 01-20190810

Winter adult male (January 29, 2019): 

Black-and-White Warbler 008-20190129

The Northern Parula is another early-arriving warbler. The dense foliage sometimes makes them difficult to locate. I nearly discarded this photo because I assumed that the bird was hiding out of sight...

Northern Parula Original 01-20190909

...but look closely:

Northern Parula CROP 01-20190909

Northern Parula 02-20190909

This male Northern Parula just caught a spider:

Northern Parula 20190911

Prairie Warblers are most numerous, as they breed in Florida's coastal mangroves during May through early July and return to the interior for the rest of the year.

This male was very photogenic as it posed on a Pond Cypress in perfect early morning light:

Prairie Warbler male 03-20190910

Prairie Warbler male 02-20190910

Prairie Warbler male 05-20190910

Blue-gray Gnatcatchers often join the warblers. They also breed down into south Florida, although we do not see them here during mid-summer:

Blue-gray Gnatcatcher 02-20190909

Brown Thrashers nest locally and stay year round, but migrants from the north swell  their numbers in fall and winter:

Brown Thrasher 05-20190910

The Northern Cardinal is resident all  year round. No matter where they breed, they do not migrate and usually remain in close proximity to their nest. This male has not yet finished his post-breeding molt:

Northern Cardinal 04-20190912

In a grassy area along the path, a White-tailed Doe grazed as her yearling fawn eyed me suspiciously:

 White-tailed Doe and fawn 02-20190910

White-tailed Doe and fawn 07-20190910

A young spike buck walked out into the clearing, but moments later the trio bounded away:

White-tailed spike buck 09-20190910

Before sunrise on September 9, the dark shadow of a thunderhead out on the ocean interrupted the rays of the morning sun as they converged on the opposite (western) horizon:

Shadow of thunderhead before sunrise 01-20190909

Five minutes before sunrise, the clouds were partially  shaded by the horizon and glowed warmly:

 South shore at sunrise 20190909

South shore 5 min before sunrise 20190909

About 35 minutes before sunrise on September 15 the Harvest Moon shone brightly over the  lake:

 Harvest Moon 35 minutes before sunrise 20190915

20 minutes later, the clear sky had brightened up:

 Harvest Moon 15 minutes before sunrise 20190915

At sunrise on September 9, my shadow pointed towards the Everglades, beyond the lake. On the day of the equinox, like a sundial, it will have moved a bit more to the right and pinpoint 270 degrees, true west.

View to due west 20190909

At our location in south Florida, on September 23 the sun will rise at 90 degrees (due east) on the horizon and set directly opposite (270 degrees), but the length of day and night will not be equal until September 27. 

Factoid:  In Singapore, located almost directly on the equator, sunrise and sunset will likewise be at opposite points, but the lengths of day and night will never be equal, this year coming closest near our (Northern Hemisphere) winter solstice on December 25, when the day will still be 12 minutes and 16 seconds longer than night.) Read: Why are days always longer than nights at the Equator?   

This week I celebrated my 13th Blogaversary. Way before I started blogging (as the term became known), in the mid 1980s, I wrote columns on health care issues and uploaded  them via an acoustic modem to the Fort Worth (Texas) Star Telegram web site, StarText. This pioneering “electronic newspaper” started in 1982 and was freely accessible on a computer. 

The Star-Telegram is the nation's oldest continuously operating online newspaper. StarText was an ASCII-based service which was eventually integrated into the paper's current website. 

I composed my columns on the world's first "laptop," a Tandy TRS-80 model 100 computer, upgraded to 24 KB RAM and which ran on 4 AA Batteries. In 1989 I spent $999.00 upgrading to a Tandy 1100FD laptop with an impressive 640 KB RAM and a 3.5 inch floppy drive. Adjusted for inflation, it cost $2500 in today's economy.  

= = =  = = =  = = = =  = = = = =

Linking to Misty's  CAMERA CRITTERS,

Linking to Eileen's SATURDAY'S CRITTERS,

Linking to SKYWATCH FRIDAY by Yogi, Sylvia and Sandy


Linking to BirdD'Pot by Anni

Linking to Our World Tuesday by Lady Fi

Linking to Wild Bird Wednesday by Stewart

Linking to Wordless Wednesday (on Tuesday) by NC Sue

Linking to ALL SEASONS by Jesh


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