On August 17, 2010, I sat on a carpet sample off of SR 229 at the north end of Delaware Lake, watching the Osprey nest there through a spotting scope. Atop the platform’s nest stood a lone Osprey with chocolate-colored feathers fringed in white, the plumage of a youngster. Even before I aged the handsome bird, I was happy to see only one on the nest because a second nestling must have fledged, and possibly the lone bird had also flown one or more times, but it had returned to port, so to speak. Accordingly, I declared August 17 as the fledging date for the lake’s family; the latest fledging date among 27 successful nests recorded in Delaware County since 2001.
Earlier in the season, I had incorrectly declared that the Delaware Lake Osprey must be infertile since every successful nest in the county’s prior history had started incubation in April. However, on May 21, five days after my previous visit, a female Osprey confirmed incubation when she stood, dipped her head in the nest cup, and began rolling eggs hidden from my view. As I silently celebrated this welcomed sight, a trouble-making third bird showed up to be intercepted, confronted, and chased away by the female’s determined mate, making a “soap opera” a possible explanation for an extremely late nesting. Had a prior nest, or nests, failed due to conspecies competition?
During mid-March, Ospreys began adding sticks to platforms at three lakes in Delaware County. I recorded incubating Osprey at Hoover Reservoir on April 11, and calculated a conservative first-egg-date of April 8. From the county’s first egg at Hoover until its last first-flight at Delaware Lake, 132 days made up the fish hawks’ nesting season. Since adolescent Ospreys need to hone many skills before they leave their natal territories, watchers can find their subjects on or near platforms through mid-September.
Four of Delaware County’s seven platforms produced a total of ten Ospreys in 2010. Delaware Lake’s platform fledged two just south of State Route 229. Three fledged from platform #1 while #4 raised two at Alum Creek Lake along Hogback Road south of Kilbourne. Hoover Reservoir’s original platform near Galena fledged three. All platforms stand where streams enter lakes to slow and drop silt to form shallow water over flat lake bottoms, habitats favored by fish that become visible prey for fish hawks. Knowing the flood history of an area is also important. We install our platforms on slightly higher elevations on mudflats where currents have been weakest during high-water events. Even though our platforms have been safe from high water, ice flows have caused problems in the past.
When conservationists offer fish hawks safe platforms, the birds respond to promote their species, while our own species can enjoy watching Ohio’s most visible and tolerant raptor. Every platform has been installed to attract nesting birds while also providing the best viewing opportunities for people. Perches that jut out from nests are positioned so nest activities are totally visible from shore.
History: 1982 – 2010
The first Osprey platform in Delaware County, and possibly the first in Ohio, was installed in 1982 over mowed land next to “Red Cross Cove” in Delaware State Park. The cove is located just north of the park’s marina. Thirty years ago, the Red Cross used the cove for summer canoe lessons. A team of four replaced the original platform, a plywood octagon, in 1996. The platform has never hosted nesting Osprey because two rangers and I had placed it in the wrong habitat. Fish hawks don’t like to nest within gliding range of the Great Horned Owl, their number one nemesis. Horned Owls like to dine on sleeping Ospreys.
In 1989, Osprey expert Alan Poole published his 246 page book, Ospreys: A Natural and Unnatural History. Eight years later, Poole’s book provided guidance for a team of adventurous conservationists that wanted to attract nesting Ospreys to Alum Creek. A written proposal was presented to three government agencies to win permission to proceed, and Consolidated Electric Cooperative made the project possible by delivering three recycled electric poles to the Alum Creek site. The first “properly placed” platforms in Delaware County were installed during Super Bowl Weekend in 1997. Six of the seven installers were fifty years or older at the time, proving that not all men elect the passive activity of watching younger men play football.
A pair of Ospreys showed up at Alum Creek on July 11, 2000. The determined pair inspected the three platforms there, built a nest on one, and spent hours perched side-by-side on dead tree limbs along the shore. Unfortunately, the young birds had arrived too late in the summer to lay eggs, but they had bonded with the site and each other and their love prevailed.
The pair returned early enough in 2001 to raise the first Osprey family along Hogback Road where 37 Ospreys have launched new lives during the past ten seasons. Usually, two pairs nest each year. Delaware Lake has produced 13 fish hawks since 2003 on a platform installed by five Ohio Division of Wildlife personnel with Dick Phillips and me assisting. Since 2006, Hoover Reservoir also has produced 13 Osprey on a platform that Dick Phillips and I installed on September 10 + 11, 2002.
Remarkably, Osprey platforms in Delaware County have added 63 Ospreys to the sky since 2001.
Beyond the Nesting Season
In order for fish hawks to have productive seasons, a certain amount of maintenance must take place. Post season maintenance began this year on September 5 when Dick Phillips and I met at Hoover Reservoir’s boardwalk in Galena. The lake was eight feet below summer pool and our mission was to walk across the exposed mudflat to platform #2 where we would straighten the signposts there. Four evenly spaced signposts had stood one hundred feet from the platform since it was installed in October 2008.
The outdated “endangered species” signs atop the steel posts became irrelevant before the 2009 nesting season after Osprey had been reclassified from “endangered” to “threatened” due to successful reintroduction efforts by the Ohio DNR, Division of Wildlife (ODOW). I had designed the wooden sign holders to also serve as perches for fish hawks, kingfishers, gulls, swallows, and other feathered creatures. Osprey-watchers frequently spot fish hawks on sign-perches as they rest, preen feathers, or rip fish. Hopefully, man-made perches are part of the birds’ attraction to their nest sites.
By 2010, winter winds had pushed ice into three of the signs at Hoover, causing them to lean. A fourth sign had been snagged and pulled out by a floating tree. Less than one hour of labor was needed to straighten and reinstall the signposts and to remove their aluminum signs. Hopefully, Mother Nature will be kind this winter and the sign-perches will not need our attention next spring.
Deterring Canada Geese
Preventing Canada Geese from claiming platforms is a major chore. Canada Geese tend to nest earlier than Osprey, and if they claim a platform before Ospreys arrive, then one day of intense combat will follow with geese winning in some cases. If a used Osprey nest is allowed to remain on its platform for the entire year, then a goose only has to add its own down feathers from its breast and belly and go about laying eggs. However, since geese cannot nest on bare platforms, we remove used nests from platforms whenever possible. The law allows this practice only after the birds complete their regional migration as they work their way to South America. As it should be, the law is a good guide for Osprey management since we want first-time migrants to see old nests and know that Ospreys have nested. We want memories burnt into raptors’ brains so Delaware County will be a possible destination when their hormones drive them to search for nesting sites. Milton and Mary Trautman’s Annotated List of the Birds of Ohio lists Osprey fall migration as September 1 through October 30, so when Hoover Reservoir is dry enough, the old nest atop platform #1 will be removed sometime after November 1.
Each year, the Army Corps of Engineers at Alum Creek Lake lowers the lake level from its summer pool of 888 feet above sea level to 885 feet for the winter. Last year, the Corps lowered the lake’s pool between October 13 and 20. After allowing enough time for the exposed lake bottom to dry, and for our actions to be legal, an Osprey team will wade the mouth of the creek and haul an aluminum ladder to all platforms with nests or sticks. A ladder strap will hold the ladder against the platform to make it safe to pry the old nest from its base. During some years, we have trudged over the frozen creek channel, but frozen nests are very difficult to remove.
Delaware Lake’s platform stands 28 feet above the lake bottom, requiring a 30-foot ladder and a fearless climber to clean it. Needless to say, it has never been cleaned, nor have geese ever attempted to nest on it, so we don’t fret about removing the huge nest with its multiple layers of sticks and other debris.
It is always fun to examine old nests to find explanations for earlier observations. Old nests completely cover the three-foot-square platforms, and when first inspected, they look like dirty trampolines littered with fish scales and sun-bleached catfish skulls. Occasionally, we find unhatched goose and Osprey eggs. A matted layer of non-woody vegetation, four or five inches thick, covers most of the nest. Large sticks, no thicker than broom handles, lace throughout the debris, but are most visible around the edges. When nests are being constructed, we know that eggs are expected when the birds start delivering nonwoody vegetation to the center of the nest. Once incubation starts, the male delivers additional sticks to make a “bunker” that partially hides the female. While the adults incubate eggs or brood young, they constantly move sticks toward the nest edge, perhaps as compensation for nothing else to do.
Volunteers Make it Happen
Since 1996, more than two dozen volunteers, representing both genders and ranging from two grade-schoolers led by their father, to individuals more than seventy, have helped to clean nests, install new platforms, stack rocks around platform bases during “rock parties,” and have worked to repair and straighten platforms after damaging ice flows. Also, journalists writing for newspapers and magazines are part of the Osprey’s team. Photographer Jim Martin has contributed his captured images for numerous articles to promote Osprey conservation.
In Central Ohio, many conservationists enjoy working in the Osprey’s corner for its continued success. We look forward to the Osprey’s return in 2011. Raptor on!