Friday, April 23, 2010

Sunday 4/18/10 falcon survey on Mississippi River



I set off early Sunday morning and made my directly to the Agri-Bunge stack house in McGregor, Iowa. I searched the usual spots the adult male falcon has been known to use without locating him. I humped my telescope and tri-pod up the nearby bluff to get a view directly into the nest box mounted to the roof of the stack house. What a physical way to start the day by trudging up this bluff! Once top side and scope set up, I could easily see the head of an adult falcon incubating in the nest box.

Next site was Leo’s Bluff near Waukon Junction, IA. As I was nearing the area directly below the cliff, I saw the adult male falcon heading out over the river with a snapping wing beat. I knew he was on a hunt. By the time I got my car pulled over I lost sight of the hunting falcon. He returned about five minutes later without prey. I was setting up my scope to verify band status when a Red-tail hawk flew directly in front of the cliff face. I thought Why is this guy not getting hammered? Just then, the adult male falcon struck the hawk with such force that I could hear the strike and saw many feathers flying. The falcon got in one more strike before the wounded hawk made it to safety in the trees.


I then drove to the Lansing Power plant cliff and saw an adult falcon perched on the new cliff mounted nest box. We installed this nest box about ten feet above the favored ledge. Each and every time the falcons nest on this ledge and not the nest box their eggs are eaten by raccoons. However, I noticed fresh mutes on the ledge and now wonder if the female is on eggs on the ledge and the adult male falcon is using the nest box perch as a sentry spot. I will need to access the roof of the plant turbine building or cat-walk up on the stack to get a good view of the cliff nest box and nearby ledge.


The nest box we mounted about nine years ago on Dead Cow Bluff just upstream of the Lansing power plant had an adult falcon perched out front of the nest box. David Litton, Tom Griffin, Dave Kester, Neil Rettig, Maggie Jones, and myself mounted this nest box. Humping the nest box, pea-gravel, tools and ropes to the top of this bluff took a bit of effort. However, after all of these years, it appears it was an effort worth while.


I checked Blackhawk and Reno Bluffs without finding falcons. I spent about 30 minutes at the Shellhorn cliff south of Brownsville, MN without locating a falcon. I did not find a falcon at this cliff on my last survey and now feel that the adult falcons that were on site in mid March have moved elsewhere.


I saw one falcon at Great Spirit Bluff perched on a dead snag close to the nest box, and one adult falcon strafing a Turkey vulture at Queen’s Bluff. I spent quite a bit of time at the cliff south of Homer, MN where on previous trip I observed a falcon. No falcon on this trip. I spent quite a bit of time at Homer Cliff north where we have had successful nesting before but no luck in 2009 or again in 2010.


I originally had planned on making my way to Red Wing, MN but was anxious to meet with Gary Grunwald at Twin Bluffs near Nelson, MN. I crossed over at Winona and spent some time at Castle Rock without finding a single falcon. No falcons seen at Fountain City, WI.


The falcons at 12 Mile Bluff are seen more often on the cliff then at the nearby Dairyland Power nest box up on the stack. John Thiel was able to get the band number of the adult male who is a falcon named Mark (23/M), a 2002 HY falcon from Castle Rock


Maassen’s Bluff has no falcons at all this year. This is very strange, since we have had adult falcons at this cliff for many years. Whether or not they successfully produced young, we've had an adult pair on territory for a long time. Not this year, though.


I met with Gary Grunwald down below Twin Bluffs at Nelson, WI. After waiting for about 30 minutes, we saw an adult male falcon chase off intruding vultures. He then flew to a live cedar tree and disappeared. Gary and I next made our way to Maiden Rock and quickly located an adult male falcon that is banded but I don’t think it is Gunnar, the captive bred falcon that has nested at this cliff in the past. We didn't find a falcon at West Bluff, although the land owners have reported seeing two falcons drive away eagles.


Gary and I made our way back down stream, stopping for a few minutes to try to get the band number of the adult male at Maiden Rock (no luck). We ended the day at Twin Bluff, where we were shocked to find vultures flying across the face of the cliff and even perching on the bluff top without being harassed by a peregrine falcon.


We have had adult falcons at these cliffs in past seasons that do not have resident falcons this year:


  • Castle Rock, WI
  • Masssen’s Bluff,WI
  • Homer, MN cliff
  • Fountain City, WI cliff
  • Shellhorn cliff, Brownsville, MN
Bob Anderson

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