Blog # 394 Three Wee Bobbleheads— Moana, Makani, and Lani

The Stewart Park Osprey catching a white sucker, courtesy of Cynthia Sedlacek.

The third Salt Point hatchling made its debut into the world on Saturday, May 28, in the early morning and immediately joined its siblings as they slept in a pile. About an hour later, all three hatchlings made their way over to Ursula who was tearing apart a yellow perch. All three wee bobbleheads gaped with their beaks wide open trying to get the attention of their mother. 

Two days later, the third chick can hold its head high and wobble its way around the nest to stay near its mother, the source of food and warmth. Osprey hatchlings are born “semi-precocial” or semi-helpless, down covered with eyes open and able to eat within a few hours of birth. They stand weakly with their heads bobbing and begging at any movement. The three will collapse into a huddle, each seeking the warmth of their siblings. 

This year’s names for the hatchlings will be borrowed from the islands of Hawaii, a state rich in natural resources, rich history, and amazing topography. However, no Ospreys have survived the long ocean crossing to colonize the islands. Three Hawaiian spirit names have been chosen for this year’s hatchlings. The eldest chick is Moana, meaning ocean, who is one week old today. The middle chick is Makani (muh KAH nee) for the wind. The third and youngest is Lani, named for the sky. Despite their age differences, this year’s hatchlings are relatively the same size. The staggered birth order helps to ensure that at least one chick (usually the oldest and largest) is likely to survive. 

In most animals, hatching or birthing is synchronous meaning that offspring are born at the same time, or within a short time of each other. Some bird families, including raptors like Ospreys, hatch their 

Ursula feeds her three young hatchlings.

eggs asynchronously, where a clutch of eggs hatch days apart rather than hatching at the same time. Female Ospreys decide when to begin incubation, as egg development does not begin until the adult warms the eggs. Incubation begins as soon as the first egg is laid, rather than waiting until after the last egg is laid. As the earlier eggs were incubated and began their development sooner, eggs hatch over several days rather than all at once. Female Ospreys lay between 1-4 eggs, at intervals of 1-3 days apart. It regularly takes over a week until the full clutch is laid. The last chick to hatch often faces a higher risk of mortality due to being younger and lighter than its siblings. One theory is that asynchronously acts like an insurance policy. If the earliest chicks are lost to predation or damage, the later ones may still survive. 

Another possible reason for asynchronous hatching is that females may prolong the time between laying to allow them time to provide each egg with enough food. Laying depletes the female birds' own stores. Staggering laying allows the female to recover and replenish nutrients between each egg.

Other theories state that asynchronous hatching decreases loss from predation, as it reduces the period that the whole brood is vulnerable and exposed to predators. Having eggs hatch over a period of time also allows the parents to take advantage of unpredictable and rapidly peaking food resources. It might be a way to reduce the ‘peak energy load’ or the amount of time that parents have to care for all the chicks at the same time. Despite these strategies, it appears that having nestlings of different sizes can often result in the death of the last hatched chick, reducing chick survival and therefore adult reproductive success.

Studies found that despite nestling mortality being higher in asynchronous broods, the mean nestling weight of fledged chicks is heavier. This indicates a higher rate of survival of the fledglings into adulthood. Osprey chicks are renowned for putting on 70% of their body weight within the first four weeks of their lives. By the time they migrate, they have adequate reserves to support them on their migration to South America. The ability of asynchronous chicks to fledge at a heavier weight than their synchronous counterparts increases their chances of surviving the challenging post-fledging period and in the long term, improves the species' long-term breeding and reproductive success.

The best time to view the hatchlings is during feedings, when three fuzzy brown heads pop up, wobbling like drunken sock puppets with long necks and sharp beaks. Their small bodies and wings, covered in tan peach fuzz owing to simple unbranched feathers designed for warmth, strain to get a morsel of food from their mother,  Their undeveloped claws are barely noticeable, and their growing beaks are unready to rip fish apart. A whitish “egg tooth”—a hardened part of the upper mandible used to crack the eggshell—will be shed as the bird grows.

Nestling Ospreys cannot regulate their body temperature until they are two to three weeks old and must depend on their mother’s body to stay warm and dry. Hatchlings are susceptible to chills during prolonged rainstorms in these early weeks and must be kept well-covered. Wet chicks are far more likely to perish when stressed. In one study in Massachusetts, a severe rainstorm lasting two days killed up to 30% of the chicks. The loss was due to the difficulty of hunting food in such weather. The Salt Point nest is located at the far western reach of Salt Point where the mouth of Salmon Creek meets Cayuga Lake. As mentioned in Blog #392, Salmon Creek is usually calmer and easier for Orpheus to fish when Cayuga Lake is turbulent, and it is filled with white suckers, yellow perch, and brown bullheads.

Orpheus fishing in a shallow stretch of Salmon Creek, courtesy of Cynthia Sedlacek.

Young Ospreys are under tremendous selection pressure to grow quickly and take to the sky to escape predation and prepare for migration. In two short months, the young ospreys will be as big as their parents and getting ready to leave the nest. Their thick-down plumage will be replaced by feathers in 10-12 days and their crops, a food storage organ, will develop. The hatchlings literally grow before your eyes. Keep your eyes on the Salt Point Osprey Cam to watch the youngsters grow and mature.

Eyes to the sky!

Candace

Candace E. Cornell 

Friends of Salt Point, Lansing, NY

Cayuga Lake Osprey Network

EYES ON OSPREYS!

WATCH!

Salt Point Osprey Nest Cam 2021

https://www.youtube.com/channel/UCjfnE74qpNoi7nG3mfL-TIQ

READ!
On Osprey Time—A Blog  on the Ospreys of Salt Point

https://www.lansingrec.com/parks/20-salt-point/

salt-point-articles/27-on-osprey-time 

VISIT!
Cayuga Lake Osprey Trail

https://www.arcgis.com/apps/MapJournal/index.html?appid

=fb09815967204bfc9386fe2d4d78f1b0

HELP PROTECT OSPREYS:

• Stay 300 feet away from nesting sites during the breeding season. 

If the Osprey vocalizes, you are too close! Back off Immediately.

• Carry binoculars to view wildlife from afar.

• Help keep local waters clean, healthy, and safe.

• Recycle used fishing lines, twine, and nets, which can kill Osprey.

• Join the Cayuga Osprey Network and volunteer to help monitor Osprey nests: cec222@gmail.com.