OSPREY (PANDION) CHOOSE TO NEST ON STEEL PYLONS IN SUFFOLK COUNTY, NY

 

August 18, 2024

In recent weeks I have observed a pair of Osprey (Pandion haliaetus ) nesting at the top of a 36 meter (118 ft) steel, single-pole electric transmission pylon just west of Peachtree Lane at: 40. 56. 21 N, 73.00.35 W in Brookhaven, Township, near the village of Mount Sinai, on Long Island in New York’s Suffolk County.  The pylon nest site is well away from surface bodies of water such as ponds, marshes or the marine environment. Long Island Sound is about 2 miles (3.2 km) from the nest. The only significant fresh water ponds are located in a golf club about two mies from the nest site. The Peach Tree Road nest site is about 2 miles due south of the Long Island Sound shore, and two miles (3.2 km) from Mount Sinai Harbor. It is also about four (4) miles from Port Jefferson Harbor which is located to the northwest. 

 The question this author asked was where were these inveterate piscivorous “fish hawks’ exploiting fish upon which they depend for 99% of their diet?  Or were they exploiting in part the small mammals such as woodchucks, marmots, field mice and cotton tailed rabbits which were all very common along the transmission line right-of-way clearings just below their nest? Or have they found adequate source's of fish? How far away did they have to fly to feed? Were they successful? 

Several examinations of the area below the 118 foot high nest revealed only fish remains which were dropped or fell from the nest above.  This author observed fragments and parts of fish bodies, such as gill covers, fish vertebral bone and ventral fins of small bony fish. The species of these scant piscine remains were not apparent.  

How far away from potential fishing sites? 

The Peachtree Lane nest site is located on the North Shore of Long Island about 1.8 miles from the center of Mount Sinai Harbor, a body of water of about 500 acres in area which is confluent with Long Island Sound about two miles (2 miles 3.2 km) to the northwest of the nest site. There are two active Osprey nest sites at the Harbor. 

Potential Fishing Sites Inland.

A number of fresh water man-made ponds are located to the southeast of the nest site or inland. Twelve of these small ponds ( estimated average size about 360 ft x 170 ft or @ 1.4 acres surface area ) are located within the bounds of the Willow Creek Country Club golf course, situated to the southeast of the nest site. The center of the Club is about two (2) miles south-southeast of the nest site. The farthest pond in this group is 1.6 miles distant while the closest is about 4,200 ft ( 0.79 miles) from the nest site. The largest pond has an area of 800 x 100 ft (1.8 acres surface area). There may be a total pond surface area in this area of about 16-17 acres at the Willow Creek Club located  about two miles (as the crow flies) from the Peach Tree Road pylon nest site 

Other than these, a solitary small pond about 1+/- acres in area (also man-made) is located just 3,500 feet (0.7 miles) due south of the nest site. 

Two gravel extraction companies are active southeast of the nest site. One of them (with no name) is located just west of Yaphank-Miller Place Road at 2.9 miles distant fro pylon site. 

While the Roanoke Gravel and Sand Pit pond is 4.5 miles southeast of the nest site. This body of water has an estimated 113 acres of surface area. 

Conclusion: 

Though the Peachtree Lane nest site is not situated on the shore of a marine embayment or of a lake, the distance to such bodies of water are relatively short. A number of small fresh water ponds occur at 3.2 km away with about 16-20 acres of total surface area. At the same 2 mile (3.2 km) distance lies the expansive Long Island Sound, which is confluent with shallow water marine bays and harbors with large areas of surface water at similar distances.  Thus the nest site seems sited in a location which provides easy access to both fresh or marine exploitation areas for Osprey at almost equal distances away. 

The 118 foot high transmission line pylon provides a structurally sound base for a bulky heavy nest and its height and metal surface provides almost absolute security from terrestrial predators. To protect the power lines from damage from growing trees the surroundings are clear cut of trees by the L.I.utility company. This tends to provides unfettered flying space around the nest as well as security from avian predators such as crows and other raptors.  Osprey may prioritize the location of a nest sites for its security from predators and its structural soundness over the distance to its fishing sites. 

While boating in Mount Sinai Harbor this author observed an osprey flying directly over head carrying a small fish in its talons. I assumed it was one of the two pairs nesting on the shore at the Harbor. The fish hawk appeared to be returning to its nest site with its prey.  As it passed over-head, a second large black bird with prominent white head appeared flying close behind the hawk. The American Bald Eagle (Haliaeetus leucocephalus) seemed to make an attempt to force the fish hawk to release its hard won prey (a small fish about the size of a sea perch, cunner or bergall). The osprey twisted and turned in the air, but encumbered with the fish held head-first in its talons, failed to out pace or out-maneuver the larger bird. Finally, perhaps to get away, it dropped the fish into the bay, where it dissapeared below the surface. The eagle swooped down over the location, but abandoned the chase and flew off in one direction, while the osprey flew in another..but with no fish. 

Note: On this date the author observed the response of the (assumed male?) Osprey at the Peachtree Lane  Nest to the presence of a Red Tailed Hawk (Buteo jamaicensis). The Ospreys ignored the presence of the hawk while it perched on an adjoining pylon about 100 meters (328 feet) away.  When the hawk flew off its perch, it passed within a 50 meter radius of the nest, the smaller Osprey, then took off in pursuit. The hawk descended quickly and flew into the forest canopy presumably to escape.

Addendum: On August 29, 2024 I observed the Peachtree Lane nest site again. The nest atop the pylon appeared to be deserted. I searched the grassy area around the base of the pylon where I observed several dried gill covers of what appeared to be clupeiform (herring like) fish and the dried head of what appeared to be a Bunker or Atlantic Menhaden (Brevoortia tyrannus). This seems to confirm that the Osprey were fishing in Long Island Sound or Mount Sinai Harbor about two miles away. 

SCIENCE BEHIND AN AIR TRAGEDY IN SAO PAULO, BRAZIL AUGUST 9, 2024

 An air tragedy in Brazil, wing icing in the tropics, supercooled droplets, Bernoulli effect, airfoils and Newton’s Third Law. 

August 10, 2024 Sao Paulo, Brazil

On Friday afternoon, August 9, 2024 a VoePass  ATR 72-500 aircraft, with 62 passengers and crew on board crashed just 45 miles short of its destination in the City of Vinhedo, while on its way to Sao Paulo City’s  International Airport at Guarulhos, Brazil. Sadly there were no survivors.  The ATR 72-500 turbo prop plane was manufactured in Europe by a ATR, a French-Italian consortium of the Airbus and Leonardo firms. Since the early 1990s this plane has had 15 air crash incidents with almost 500 fatalities. A similar plane, an ATR 72-200 crashed in 1994, in Roselawn, Indiana in which the probable cause was icing of wings. The crash caused 68 fatalities. A US Federal Aviation Agency investigation concluded with a warning to pilots not to use autopilot in icing conditions when flying these planes. 

This VoePass ATR 72 was on a domestic flight from Parana State to Sao Paulo City with 62 passengers and crew on board, when at 11.21 PM the flight, cruising at 19,000 feet, began losing altitude over Vinhedo City about 45miles NNW of Sao Paulo City. The plane dropped 250 feet in 10 seconds, then climbed back up 400 feet in 8 seconds. Seconds later it lost 2000 feet and then it began a rapid spiraling downward fall, dropping 17,000 feet in one minute. It crashed and burned among houses in the City of Vinhedo. No local residents were hurt as the plane plummeted to the ground in a clear area among homes and burst into flames. 

Video photographs published by onlookers on the ground show the intact ATR turboprop, falling, with no horizontal speed, plunging almost straight down. The video is frightening to watch since it is clear that the plane had lost all ability to fly and was in an uncontrolled deadly death spiral to the ground.  The plane provided no visible reason to fall, it appeared unaltered, there were no flames or smoke, the wings, tail and body were intact.  The ATR 72 was simply plunging straight down like a huge piece of silvery metal.

What could have caused such a crash?  

It is winter in Brazil which is in the southern hemisphere. Though Sao Paulo and Vinhedo are located in a tropical-temperate zone, at about 23 deg south latitude, close to the Tropic of Capricorn, winter is relatively mild there. (Sao Paulo is far south of the equator as semi tropical Tampico, Mexico is north of the equator.) Average southern hemisphere “winter” temperatures for August in Sao Paulo range from 60-70 degrees F during mid day.  

Since for the most part, air is heated from the bottom up, not by the sun’s rays passing through air, but indirectly by the sun heating the earth, and then the warmed earth transferring that heat to the air. For this “bottom up heating” reason the air cools at a regular rate at higher elevations. The Normal Lapse Rate is average rate at which the air temperatures drop when measured from the ground upward. That rate is about 3.5 F per 1000 feet. 

Yesterday, (Friday, August 9, 2024) mid-day temperatures on the ground at Vinhedo were about 70F.   But the air temperature at 19,000 feet was much cooler. Using the Normal Lapse Rate to calculate the approximate temperature at the ATR 72”s cruising height indicates that the air temperature aloft where the VoePass airliner was flying was probably around 4.5F.*  

Thus where the ATR 72 was cruising the air temperature at 4.5 F was well below freezing (at 32F).  Clouds at this level often contain moisture in the form of ice crystals, and water droplets which have been cooled below freezing but remain in the liquid state, these tiny liquid drops are called “supercooled water droplets”. These tiny drops of water  less than 0.05mm in diameter, are so small that even at temperatures well below freezing (32F) they simply can not organize their relatively small number of water molecules within the drop into the typical ice crystal lattice.  So they remain in the liquid state.  However, if they come in contact with a solid surface, an ice crystal, dust, or pollen particles which may act as nuclei of crystallization, they freeze instantly. 

When the leading edge of an airplane wing flies through such a cloud with supercooled water droplets,  the drops freeze instantly to the plane wing, tail, sensors like pitots, antennae and other parts.  This ice—called “rime ice”—is heavy and adds weight to the plane but it is most dangerous on the wings where it can interfere with lift.

As you would expect, the wing is what permits the plane to rise up off the ground and also provides the  “lift”which keeps the plane aloft.  The process is complex and probably not fully understood, but in simple terms we can think of the wing as an “air foil” with a cross sectional shape characterized by a flat undersurface and a slightly rounded or cambered upper surface. The wing functions as an airfoil (to create lift) only when it is moving forward through the air. In simple terms, the air flows smoothly over the top and bottom of the wing in cross section. The flow of air over the top surface is forced to speed up as it traverses the curved surface (a longer distance). It is this more rapid flow which creates lift. The Bernoulli Principle states that the pressure of a fluid in motion is inversely proportional the speed of the flow. Thus the pressure above the wing (air foil) is lower on the upper, curved, cambered surface than that of the bottom flat surface where pressure remains unaltered.  Imagine  “stretched out” or lower density molecules generating a zone of lower pressure along the upper wing surface.  This does not occur on the undersurface where pressure remains at its original higher level of pressure. 

As a result, the moving  aeroplane wing generates a region of lower pressure all along its upper surface.The longer the wing the more lift it can develop.  In a definitely non-scientific sense, the wing can be imagined as being “sucked” upward* by the air flowing smoothly over the upper cambered surface.  As long as the air can flow smoothly in streamline flow over that surface the wing provides lift (or is “sucked” upward ) and this disparity in pressure helps to keep the plane aloft.  (It is noteworthy that the angle of attack of the wing also creates lift. The angled upward wing tends to direct air downward creating a force (Newton’s Third (equal and opposite) Law) that pushes wings upward).  

Thus it is clear that any disturbance to this smooth air flow or “streamline flow” over the upper cambered wing surface,  such as turbulence caused by rime ice, can reduce the speed of the flow and destroy the Bernoulli (“suction”) effect of the upper curved surface.  This is the likely problem which caused this tragedy. 

How does ice form on wings?

As noted above high clouds at temperatures far below freezing have moisture in both solid and liquid form. When planes encounter supercooled droplets aloft ice can form along the forward or leading edge of the wing. Rime ice has a rough surface.  It causes the air to flow irregularly in what is called “turbulent flow”.  This form of air flow destroys the lift effect.  Rime ice thus destroys the rapid smooth flow over the upper wing surface. The slowed flow of air along the wing edge causes loss of lift, or when excessive may cancels out lift altogether.  On both wings,  icing may cause the plane to lose elevation instantly. When only one wing is impacted, that wing loses lift and the plane may bank sharply in that wing’s direction, causing the aircraft to begin an uncontrolled downward spiral. 

In the early years of flight, most planes flew well below levels of high clouds where supercooled droplets would likely be encountered.   When aircraft began flying at high altitudes, methods to control icing on wings became essential for safe flight.There are several methods used on the most modern airliners. One more modern solution is to direct heated air or other fluids derived from the jet engines or the prop engines to the wings when required .These “hot wing” planes melt rime ice which may accumulate on the wings and leading tail edge. Another method common on many older types of aircraft is a rubber boot which encases the forward edge of the wing. This flexible boot can be pumped up with air when necessary which causes the boot to expand and crack the adhering ice which then is driven off the wing by air flow. 

The ATR 72 model has this latter design. One problem with this system is that in cases when icing conditions are extreme or when such conditions are repeatedly encountered, multiple use of the system may form ice encrustations which break off and slide rearward only to refreeze onto the central cambered portion of the wing, beyond the rubber boot. When that occurs the aircraft  loses lift rapidly and plunge to lower levels. 

Though "icing" seems the likely cause of the tragedy in Brazil, what seems compelling when looking at the facts and circumstances from afar is often only the first hypothesis in perhaps a much more complex circumstance. We must await the full technical report on this sad air tragedy.

  One can only feel pain and sympathy for the families of the more than 60 passengers and crew who lost their lives in this terrible crash. One hopes those who investigate these tragedies can find the cause and make recommendations regarding flight safety that will make such tragedies very much less common.*  

(Though in relatively uncommon meteorological circumstances such as “ice storms” supercooled clouds may produce rain drops cooled to the freezing point. These liquid drops at freezing temperatures (not supercooled) fall into lower warmer levels of the atmosphere close to ground level.  There they strike power lines or tree limbs and branches and as they strike these surfaces minor evaporation further drops the temperature causing the drops to freeze on contact, and over time building up thick layers of ice with often devastating consequences to trees and power-lines.) 

* More recent (September 2024) reports indicate that indeed the Sao Palo crash was caused by wing icing. To this author, it seems reasonable to request that the ATR 72-500 turbo prop plane manufactured in Europe by ATR, a French-Italian consortium of the Airbus and Leonardo firms which in most circumstances appears to be a safe practical airship,  should be grounded and refitted with more modern deicing equipment than its original design system before it can be safely flown again.  Icing is not a mid latitude or cold climate issue. Rime icing can occur even close to the equator….. in Brazil.

  

*There is of course no such thing as “suction” but it may work as an idea aid.

*Normal lapse rate is about 3.5F per 1000 feet.

• (19 X 3.5F)- 70 F = Temp at 19,000 feet)) or 19 X 3.5 =66.5F, 70F-66.5 = 4.5F. 
• Brazilian meteorological company reported severe icing in Sao Paulo State at the time of the crash.