IMPORTANT: Messages from osprey experts

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Holy moly that’s gigantic !!!

George leaves perch

Nancy: Hi Nancy. No, the chick(s) do not migrate with the last adult (or any parent). They go it alone!!

“Nature of Migration
Individuals typically migrate singly, except at concentration points. Kerlinger and Moore 1989 reported that 80% of Ospreys sighted during fall over New York State were alone, 11% seen with other raptors (primarily Broad-winged Hawks [Buteo platypterus]), with maximum flock size 2 individuals. A flock of 11 was reported at Cape May, New Jersey (Dunne et al. 1988). Larger flocks (up to 92 individuals) have been reported in Cuba (Rodríguez-Santana et al. 2014) and Haiti (Crouse and Keith 1999) where the broad-front migration from eastern and (partly) central North America is concentrated as it passes through the Caribbean.
Satellite telemetry data show: (1) male-female differences in timing of migration (females leave up to a month before males), distance traveled, and overwintering locations; (2) individuals followed for over 1 yr by satellite telemetry showed unwavering fidelity to overwintering sites and a general fidelity to migration flyways, but not to specific routes; (3) breeding pairs did not migrate or overwinter together (Martell et al. 2001a, Martell et al. 2014); and (4) adults do not migrate with their offspring (MSM).”
(https://birdsna.org/Species-Account/bna/species/osprey/distribution)

“MIGRATION
1. Do Osprey pairs migrate and winter together?
Ospreys mate for life, as far as we know, but part ways each year for the fall migration. They migrate as individuals, not in groups or flocks. Usually, females leave the nesting area first, followed by the males. Mates do not see each other again until they return to their nest in spring. It would be a very rare coincidence if a pair ended up in the same wintering place.

2. Do the young migrate and winter together with parents or each other?
The young are left behind when parents migrate. A few days to several weeks later, the young take off, too. Each one finds its own route south and winters in a different place, just as the adults do.

3. When do the young migrate back north? Do they return to the place of their birth nest?
The young remain in the vicinity of the winter home and generally do not migrate north their first spring. Rather, they remain near their wintering area for another year until they are almost two years old. If young survive to the spring of their second year, they head north, but they do not necessarily return to the place of their birth nest. In fact, they may return to anywhere within a hundred miles of it. Chances are they will never see their parents, or each other, again.

4. How do Ospreys know when to start their migrations?
This question is hard to answer. Many birds respond to changing day length that at some point triggers migratory preparation, such as adding body fat to fuel the long trip. Then, environmental conditions such as wind direction and speed, atmospheric pressure, temperature or some unknown input or combination click in the birds brain, turning it from a lethargic resident into a migrating machine. Quite literally, a bird will be perched resting one moment and the next will be off like a shot out of a canon. The perplexing thing about the influence of day length on birds that winter in the tropics is that the length of daylight does not change much in that region. So there are likely many factors detected by the birds that prepare them for migration and then send them off at almost the same time each year.

5. Do Ospreys follow the same route north that they took south?
The return migration is almost always the mirror image of the fall migration. A bird that we have tracked on Nantucket, Señor Bones, migrated south in the fall and north in the spring in 2011 and in 2012 along almost exactly the same path. Minor variations occurred when he was flying over the Caribbean and over the Straits of Florida between Cuba and Florida; these variations were caused by drift with the prevailing winds at the time of the different flights.

6. How do Ospreys know where to go that is, how do they navigate to find their way back to their nests in the spring?
Ospreys use many methods to navigate. Since they do not migrate as a group, but as individuals, they cannot learn from each other. Some studies have shown that birds migrate using celestial cues, such as star patterns, or the position of the sun through the day and at the time of year. Others have shown that the earths magnetic forces aid them in migration. Some learning goes on through trial and error. Once a bird navigates successfully, it almost appears as if it has its own GPS navigational system to guide it next time around. The long and short of it is that we do not know for sure how they do it, but we do know that whatever methods they use, they can travel with remarkable accuracy from place to place.

7. Do Ospreys eat during their migrations or do they rely on fat stores to fuel them?
Ospreys fish along the way to keep up their strength. It appears that most fishing takes place early in the morning before they start the days flight, or during rest stops lasting a day or so along the way. This varies depending upon the distance traveled, the success of earlier fishing attempts, etc. Ospreys do not appear to fish when they travel out across large bodies of water such as the Straits of Florida or the Caribbean Sea.
What are the greatest dangers to Ospreys during migration?

8. One major danger is weather, especially when crossing large bodies of water. For instance, Ospreys crossing the Caribbean or the Straits of Florida can be blown off course if they fly into a strong headwind or get caught in a severe thunderstorm. Anything that slows their flight and increases the time it takes them to make the crossing could drain strength or fat reserves (their fuel) and put them at risk. Worst case, they may have to ditch into the water, or if they do make it to land somewhere, they may be too exhausted to fish to regain their strength. Another major danger is being shot by humans. This could happen anywhere. However, birds migrating in this part of the world are particularly vulnerable when they fish in private and commercial fish farms/ponds in the Dominican Republic, Haiti or Cuba. Many of the farms are owned by local people living at or near subsistence level, who do not take kindly to anyone or anything that steals their fish.

9. What happens when one mate migrates back to the nest before the other?
The longer the time interval between mates arrival at the breeding site, the more likely it is that the first to arrive will attract or be attracted to a new mate. Yes, Ospreys do mate for life as far as we know, but that bond needs to be reinforced each spring by the arrival of the second mate. If too much time elapses, a bird will accept another mate since the instinct to breed is far greater – and more important – than the instinct to wait for a mate that may have perished over the winter.

10. What happens if an Osprey returns to find his or her partner with a new mate?
In most cases, the late returning bird will drive off the new bird as the bond between the old mates will be stronger than the newly formed bond between the old and new mates, especially if the new mate is a young bird. We often see three Ospreys on a nest and conflicts between two of them early in the nesting season. These conflicts are usually short in duration and no one gets hurt in the process. However, once I found an adult Osprey dead in the nest while two adults went about their business of egg laying and rearing young. I do not know if the dead bird was a former mate or an intruder.”
(http://www.jamaicabayosprey.org/faq-about-ospreys)

“Migrations:
There are two distinct populations of osprey with respect to lifestyle, the Residents and the Migrants. Residents are the ones, which breed in the subtropical latitudes in winter; they either stay in the same area all year round or move only locally during the non-breeding season. The other ones are the Migrants, which nest in the temperate latitudes and fly off each autumn to spend the winter in the tropical regions.

North American ospreys start migrating south to their wintering grounds in Central America and in the northern parts of South America, around mid-August. By early September, most nesting colonies in the northern latitudes are empty. The numbers of migrating ospreys observed at selected watch points along their southward route are at their greatest during mid-September and early October.

They reach their wintering grounds by late November. During winter, the only thing an osprey does is to eat, rest, recover from the stress of the previous breeding season and prepare for the next breeding season. It has been observed that during winter, they become more tolerant of each other as they congregate in loose flocks and are even known to hunt together in small groups, a few birds hovering over water, looking for fish might also stimulate others to join in the frenzy.

Adult ospreys start leaving their wintering grounds in early March, by late March, more than half of the wintering ospreys have left the wintering areas, for their natal nesting grounds.
Yearling ospreys stay on their wintering grounds for another eighteen months, returning to their natal nesting grounds at the age of about two years.

Two-year-old ospreys however, leave the wintering grounds much later than the adults, and may reach their natal nesting grounds as late as June, by then; they are already too late to breed. However, pre-adult ospreys may become a nuisance to the breeders, because they try to take over nest sites and may interfere with the breeding pairs, as they explore and search for nesting sites of their own. They are also sometimes known to replace a partner in a breeding pair if it dies or is incapable of performing its duties.

Ospreys arrive back at their natal nesting grounds by early May.” (http://www.glenlakesfoleyal.com/html/osprey_information.html)

Another website about migration: VIMS VIRGINIA INSTITUTE OF MARINE SCIENCE @ http://www.vims.edu/bayinfo/ospreycam/about_ospreys/

Aww…poor fish!…reminds me of those singing fish 🐟 some people have for decor

Clever!

Kelb Malti ……very funny and clever CarolV!😆😉

After George left, Squirmy’s shadow showed from the right. She must have stayed on the nest to eat, as she walked in to view some time later. Stayed for a few mins. then went.off.

Pics

Isabella— thanks for all the different nests. Amazing!!!!