Osprey - a sentinel of clean water
Osprey - a sentinel of clean water!
Marla Mertz, Marion County Conservation, with help from Ron Huelse, Red Rock Lake Association Save the Lake committee member, August 2014
The Red Rock Lake Association formed a committee that is concerned about the amount of sediment that runs into Lake Red Rock.
Marla Mertz, Marion County Conservation Board naturalist, participated in a four year contracted program for the restoration of osprey to Lake Red Rock and the surrounding communities and another three years of osprey placement. The program consisted of partnering with the Iowa Department of Natural Resources (DNR), Minnesota DNR and Wisconsin DNR. A “hack tower” was constructed at Elk Rock State Park for the purpose of placing young osprey from northern Minnesota and Wisconsin for release. When the birds were physically ready to fledge, the doors on the hack tower are opened and the osprey chose to leave the safety of their shelter, they relied upon their genetic blueprint for the survival to hone their skills as a fish-eating bird. As their hunting skills were being worked on, supplemental fish was placed at the hack tower so they osprey had support in feeding. They stayed independent until the first cold north winds of September prompted their migration journey to South and Central America and await their return 22 months later.
I was given the task of photographing these great birds of flight during their fish consuming ritual. This DNA blueprint provided the survival skills on Lake Red Rock to provide the necessary tools for the birds to sustain life by demanding perfection of aerial skills and fishing prowess. The opportunity to follow this majestic fish-eating bird was exciting to watch because these birds had no teacher other than years of genetic coding to fish for their survival. How lucky can a bird be to be placed in an uncompromising position of learning what generations of previous ospreys has given this bird for survival?
What makes suitable water conditions for the osprey to fish successfully? I have watched as these birds made feeble attempts to capture the fish, plunging feet first into the water to capture fish with their talons. Nature is giving us the opportunity to watch and observe these birds at work. The best scenario of comparing this bird’s vision for hunting in water and considering light refraction for capturing their food would be a bowfisherman hunting for carp. Underwater targets are not where they appear, due to the water’s refraction of sunlight rays. Sedimentation, turbidity, and chemical infusions from fertilizers and pesticides can change the present waterway into an opportunity of survival. To learn more about sedimentation and turbidity check these out:
Try this: Drop a penny or a rock into a pool or large bucket of water and try to reach down to remove it. Is it in the same place that you thought it was?
How can we help our waterways and water corridors?
What is necessary for water to be clearer with a minimal amount of sedimentation? Can Lake Red Rock be a home to fish eating birds, as well as a home for outdoor enthusiasts wanting to enjoy this natural resource – a resource that could take a terrible plunge prior to 2069? According to US Army Corps of Engineers, at current sedimentation rates Lake Red Rock will become wetlands with minimal recreational opportunities before 2069.
Buffer strips maintained between crop lands and pastures and adjacent waterways can help minimize pollutants leaching into the water. Buffers are strips of land with permanent vegetation designed to intercept storm-water and snow-melt runoff and minimize soil erosion. These buffers can reduce the amount of sediment and pollutants carried by runoff to nearby lakes or streams.
Soil particles accumulating as sediment in a river can reduce dissolved oxygen levels and suffocate organisms and reduce sunlight needed by aquatic life. Sediment often carries pollutants such as phosphorus, a nutrient in fertilizer. These nutrients cause excessive growth of algae and aquatic plants, deplete the oxygen level of water and degrade water quality. Soil microbes and grasses in buffer strips absorb these excess nutrients and protect surface water resources.
Farmers use buffer strips and other ‘best management’ practices like winter cover crops and no-till practices to help control erosion on their land. Buffers help trap snow and reduce wind erosion on their topsoil. The benefit of buffers to farmers include reduced flood damage to crops, reduced erosion and sediment loss, and reduced ditch maintenance costs. In addition, buffer strips can eliminate end rows and provide turn areas for farmer’s machinery during fieldwork. Buffer strips in agricultural areas intercept or remove pollutants (excess nutrients and chemicals) and sediment by 50% or more, 60% or more of some pathogens and 75% or more of sediment and protect surface water resources and improve fish and wildlife habitat. Buffer vegetation helps stabilize a stream by reducing stream bank erosion. The buffers that provide a shaded environment along a river help moderate water temperature, which improves conditions for cold water fish species. Buffers are a source of food, nesting cover, and shelter for many wildlife species. Continuous buffers also provide connecting corridors that enable wildlife to move safely from one habitat area to another.
Osprey need clean water, as all of us do, but their fishing strategies for sustaining an exclusive diet of fish is greatly hindered when turbidity becomes an issue. While osprey were hacked at Lake Red Rock, in hopes that they would return to nest and fish in the reservoir. No osprey have returned to nest on Lake Red Rock; they have found other, better areas to fish. Lake Red Rock may just be too turbid for the success needed for a fish-eating raptor and off-spring to survive? Osprey are seen at Robert’s Creek during migration and osprey can be seen fishing in the quieter, shallower bays of Lake Red Rock and at Robert’s Creek Park.
Assisted by hundreds of volunteers, many conservation organizations have devoted their efforts to bring ospreys to Iowa again as a nesting species. From 1997 through 2014, 291 ospreys have been released at twelve sites in Iowa. From 2003 through 2014, 164 wild ospreys were produced at 95 successful nests (duplicated locations). Wild hatched osprey may be banded as part of the reintroduction effort and receive a green project band on their left leg and a USFWS silver band on the right leg. In 2013, 18 nesting pairs had 14 successful nest attempts with 29 young produced. In 2014 there were 15 successful osprey nests produced 30 young from 21 nesting pairs. In 2015, there were 22 osprey nest attempts that were known / reported with 18 successful nests that produced 38 young.
Female Y8 (she was hacked at the Lake Red Rock tower in 2006) along with a mate that fledged three young on a cell tower nest near Des Moines in 2014 will be included in this year's statistics.
In 2013, folks told us they saw Y8 with an Iowa-hatched male (the bird was wearing a green band). In 2014, we have pictures of her with another bird that could also have been hacked from the Lake Red Rock Tower, we just can't confirm his Iowa band letters (purple band). Thanks to B Manning and C Hansen for watching Y8 this summer, sharing their photos, and helping us figure out the mystery of who is with Y8! After looking at several pictures, we're fairly sure the project band is a faded purple band CN. That osprey was hacked from the tower at Don Williams Park near Boone, IA in 2006.
Osprey are highly regarded throughout the world and is the only truly aquatic raptor. The Osprey are also neotropical migrants (migrate to South and Central America) adapting from fresh water to saltwater.