You are seeking a small cache on Birds Tree Island in Green Bay. The island is rocky and hazardous. Finding a good landing spots for a boat is tricky. Sandbars and other navigational hazards abound. Be sure you know the water if you approach with a powered craft. We used a kayak to place this cache. It is a 3-mile round trip.
You are looking for a medium-sized, stainless steel water container. Inside that container is another container with a micro-log. This cache is not designed for swag, although items less than 1" around will fit in the cache. PLEASE REHIDE WELL to protect from non-geocachers and the elements.
At one time, Grassy Island covered a wide expanse in the Bay of Green Bay. However, in 1867 a channel 200 feet wide by 13 feet deep was dredged from the mouth of the Fox River straight through the middle of Grassy Island, cutting it in two, and out into the Bay. The eastern half of Grassy Island contained two range lights. Here is a picture of the island in its navigational prime:
Dredging in the harbor continued on an almost annual basis throughout the years, and the original channel through the island was successively widened on numerous occasions, with each widening operation being performed on the west of the channel opposite the range lights.
Looking south, so the eastern island (what is now Birds Tree or Lone Tree Island) is on the left.
Due to low water levels in the mid 1960s, the island chains became a near-marsh. This picture is remarkable when compared with the current state of the bay. Note that the range lights are still in position:
Eventually, the range lights outlived their purpose as navigational aids, and in 1966 the decision was made to destroy the lights in place, and to widen the channel through what was left of the east side of Grassy Island. The range lights have been relocated to the Yacht Club where they can be seen by the public boat launch. At times of high water, the islands were nearly submerged, but even in the 1970s, there was much more terra firma than there is today:
Severe erosion due to high water and wave action eroded much of what was left of the islands. More information is available at: http://wisconsin.sierraclub.org/PDF/CatIsland_CleanLakes_0803.pdf
Today, the islands are known by different names. They are alternately referred to as the Grassy Islands or as the Cat Island Chain. The two islands above water are Cat Island (the western half) and Lone Tree Island (the eastern half), sometimes called Birds Tree Island. Bass Island and Willow Island (to the north) and even Grassy Island itself (to the south) have been under water for some time.
A restoration project of the Cat Island Chain has been laid out since the early 2000s but thus far the project is on hold. Today, the islands remain uninhabited and relatively unvisited except for duck hunters in season and the occasional angler or sightseer.
Your destination awaits...
The cache is hidden near the spot of the south range light
Looking back from GZ
Sunrise and calm water on the Bay