Thirty adventurous people were treated to a fun filled night during the Friends' sponsored Owl Prowl on Oct. 21st. We walked only a short distance before hike leader Tom Uttech tried calling in Wisconsin's smallest owl. Within minutes the weak tremolo of a single saw-whet was heard about 100 yards away.

Its faint call was coming closer and closer until suddenly two Barred Owls flew in, landing only a few feet from the road. They, too, had heard the saw-whet owl and come in for a possible late night snack. The saw-whet disappeared while the barred owls' "Who cooks for you, who cooks for you all?" calls echoed back and forth just over our heads. They continued to entertain us for over 5 minutes while co-leaders, John O'Donnell and Carl Schwartz, scanned surrounding trees for their silhouettes.

As soon as they zeroed in on the owls' location, John and Carl turned their spot lights on the pair. The barred owls continued to hoot even while being in the limelight. Eventually the larger barred owl, presumably the female, flew off leaving its bewildered partner behind. He called for his mate for a short time before he, too, vanished into the woods. When the birds were out of sight the group broke its silence and exploded with questions about the experience. Their first question being "did we stage this performance?"

With time to spare, the group moved south to the Field Station's boardwalk. Winds had calmed and clouds cleared revealing a beautiful moon. This time our guides played screech owl calls. After numerous repetitions, a faint reply came from a distance but the songster never ventured any closer. Before calling it a night, the leaders attempted to call our state's largest owl. Although the Great-horned Owl didn't return their calls, bill snapping and moving branches clued us in to its presence. Four species of owls in two hours – not bad for one night! "Prowlers" who weren't quite ready for bed were invited to follow Tom Uttech home to try to call in a Long-eared Owl in his neighborhood. A few "night owls" took him up on the offer.

See the Calendar for information about the next Owl Prowl.

--Mary Holleback

Despite being called a bog, the Cedarburg Bog actually highlights a number of successional stages of wetland development from open water to emergent aquatics, sedge meadow, shrub carr and eventually swamp forest. Additionally, it is an atypical example of a “string bog”.    

A bog is a wetland type that accumulates acidic peat, a deposit of dead plant material. From a hydrologic perspective, true bogs depend only on rain as their source of water. However, the Cedarburg Bog actually does have some spring water flowing through it. From this view, the Cedarburg Bog is a fen, a wetland with major groundwater inflow influencing its water chemistry.

Fens are characterised by their water chemistry, which is neutral or alkaline, with relatively high dissolved mineral levels but few other plant nutrients. They support a wide range of animals and plants, many of which are tall marsh plants growing closely together.

Fens are distinguished from bogs, which are acidic, low in minerals, and usually dominated by low-growing plants including Sphagnum and other mosses.

Fen was once thought to be a phase in the natural succession from open lake, through reedbed, fen and carr, to woodland, or as the peat develops and its surface rises, to bog. Now, it is more generally recognised that fens are persistent habitats whose existence is dependent on the availability of water.

Carr is the northern European equivalent of the wooded swamp of the south-eastern United States, also known in the United Kingdom as Wet woodland. It is a fen overgrown with generally small trees of species such as willow (Salix spp.) or alder (Alnus spp.). A list of species found in a fen therefore covers a range from those remaining from the earlier stage in the successional development to the pioneers of the succeeding stage.

Fen also merges into freshwater marsh, when it develops more in the direction of grassland. This is most likely to occur where the tree species of carr are systematically removed by man for the development of pasture (often together with drainage), or by browsing wild animals, including beavers.

The water in fens is usually from groundwater or flowing sources (minerotrophic) with a fairly high pH (base-rich, neutral to alkaline). Where the water is from rainwater or other sources with a lower pH (more acidic), fen is replaced by vegetation dominated by Sphagnum mosses, known as bog.

Where streams of base-rich water run through bog, these are often lined by strips of fen, separating "islands" of rain-fed bog.