| Herons | ||
03/02/10 |
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The Peltier Lake GREAT BLUE HERONS are expected to arrive around March 17. Great blue herons nest in colonies and are easily spooked so people need to stay off the island. If you see any Great Blue Herons, please send Email to Mail@PeltierLake.Org. Thanks!
On March 1, 2010, the Lino Lakes Council had a workshop about the herons. Here is input provided. Suggested Heron Actions and Needs on Peltier Lake March 1, 2010, Wayne LeBlanc Summary · Flashing trees with aluminum bands against predators needs to continue. · Proactive action by hunting and/or trapping raccoons and opossum probably helps. I’ve heard hunters with hounds could be very effective against raccoons. · Signage around the island could be more specific about avoiding the wildlife refuge. · Eaglebrook has been helpful providing nesting material with stick piles and they said they would continue to help. · Continued vigilance is needed to prevent any future human disturbance. · What I’d really like to see is a return of the Black-Crowned Night Herons. Further Detail, Flashing Trees and Hunting I believe the problem with the Black-Crowned Night Herons and Great Blue Herons on Peltier Lake involved 2 phases: 1) human disturbance causing greatly reduced numbers and 2) subsequent predation. It seems the best thing we can do for the herons right now is to keep predation to a minimum while heading off any possible future human disturbance. Flashing on the trees seems to be the best defense against the most threatening predators: raccoons (and possibly opossum). Here is a picture taken Mar 1, 2010 of Marty Asleson and Tim Payne from the city of Lino Lakes installing flashing on a tree to thwart predators.
In 2005, trapping occurred on the island and along private property directly to the east of the island. In 2006, trapping was on the island only. Andy Von Duyke said despite the large number of trap nights invested, harvest was relatively small. Trapping and hunting poses problems of exposure to non-targeted species, pets and humans, but if done right, could help the herons. I’ve heard that hunting with hounds can be very effective. This has not yet been tried. The hounds go out and with their sensitive noses find most of the raccoons and tree them. Good hunters don’t have to run all over, they can hear a change in the barking and know a raccoon has been treed. The hunter can then take the raccoon out with a tranquilizer or gun. I suggest that hunting with hounds be tried if it can all be worked out. Further Detail, Signs & Eaglebrook Signs around the island currently say, “DO NOT DISTURB BIRD NESTING AREA, POSTED BY: ANOKA COUNTY PARKS.” “Do not disturb” can mean different things to different people. I think it needs to have stronger language with such words as prohibited or keep out. At Lake of the Isles in Minneapolis (see picture), signs around the islands there say, “WILDLIFE REFUGE, LANDING ON ISLANDS PROHIBITED, P.B. 4-8.”
I suggest the stronger language of “prohibited” or similar words are needed. Also, I prefer “WILDLIFE REFUGE” as there are Piliated Woodpeckers, owls and many treasured species that make their home on the island. The herons are there from about March 17 through the end of September. Eaglebrook has been helpful providing nesting material with stick piles and they said they would continue to help. I have personally seen these stick piles in use by the herons. I believe we have Art Hawkins to thank for identifying this aid to the herons. I thank Eaglebrook for their interest and help in protecting the sensitive environment. Further Detail, Continued Vigilance and Further Data I’d like to illustrate one aspect of the herons that is seldom discussed. In 1998, an entire species was wiped out, my favorite, the Black-Crowned Night Herons. They existed in substantial numbers (the chart meaning 100%) on the island but the first year the ski course was installed, ALL Black-Crowned Night Herons disappeared. Art Hawkins, noted biologist watching the island, also made note of their disappearance.
In addition, the Great Blue Herons were greatly affected the first time the ski course was installed, they seemed to be recovering 1998-2000, but then they really got hammered with it was installed again, against the agreement set by Anoka Parks, the DNR and others. I do not believe these are coincidences but rather, causes. Anoka Parks is doing a terrific job installing the no-wake zone buoys at ice out so there is no delay identifying the no-wake zone for the boating season.
Further Detail, Chicks and Nest Counts Here is a chart on the number of chicks observed in each year shown. The increase in these years is due to work of Andy Von Duyke and others by managing the predators. In 2008, a tornado touched down less than a mile from the colony. I believe the severe weather mostly missed them. The herons were very lucky. In 2009, I suspect a wind storm took out many of the chicks, however, it could have been predation or most likely, part of both. Although there were fewer chicks that year, the population still increased by 27. The nest count continues to rise (see the next chart), so hopefully, the decline in 2009 is not too much of a factor. In addition, realize, these numbers are not perfect as chicks are difficult to see in the foliage.
The number of nests in this chart shows a continued increased over the years. In the winter, the nests can be seen and counted accurately and this should be a primary statistic for the future, provided of course the nests are active. In a given year, the herons move the nests around a bit and steal sticks from one nest making another in a different place. This dynamic is easily observed in the winter by comparing nests and trees of the previous year.
Black-Crowned Night Herons, common on the island before 1998 have not been observed for 11 years. Great Egrets also frequented the island but are now absent. Although far from pre-1998 levels, I am hopeful that the Great Blue Heron colony is slowly increasing in numbers. For more information see: www.PeltierLake.Org/Herons.htm For detail, see www.PeltierLake.Org/WhyHeronsLeft.pdf “Rookery Blues”from the Minnesota Conservation Volunteer magazine is still available at www.dnr.state.mn.us/volunteer/marapr04/rookery.html
*************************************************************** We have EXCELLENT news for 2008! A total of 55 great blue heron chicks were observed in July. It is amazing that many survived the May 25 storm which had quarter size hail, 80 mph winds or more, and a tornado that touched down just a mile east of the colony. The productivity over the last few years was: THIS IS EXCELLENT! The herons are very sensitive to disturbance. People need to keep their distance. Here is some history on the herons. Before 1998, all was wonderful for the herons of Peltier Lake! Virtually every evening, Black-Crowned Night Herons squawked their “quuarrck” sound and the Great Blue Herons echoed matching ancient calls. Experts estimated there were about 1,100 nests on the large island plopped in the shallows of north Peltier Lake (see diagram). Human activity in the lake was south of the island so the herons preferred the island north end. Thick native aquatic plants and shallow waters discouraged almost everyone from entering the heron haven. (Herons only nest in colonies; they do not make single nests in back yards.) However in 1998, a slalom water-ski course was installed right next to the heron rookery. The herons, who were no longer isolated, now found noisy inboard water-ski boats with high-flying walls of slalom water-ski spray – all in their “living room.”
At the end of the year, there was great concern among area heron watchers; some observers felt that heron numbers were down. (According to DNR data, estimates put numbers down about 50%. In addition, the treasured Black-Crowned Night Herons totally vanished). I called a meeting with state experts from the DNR, county experts from Anoka Parks, city officials, law enforcement and people from the Peltier Lake Association including the slalom skiers. Experts explained the sensitive environment and an agreement was reached so that no more water skiing would be done north of the island. A couple years later, it seemed the herons were abandoning their nests. The herons were in trouble. The next thing we knew, the ski course was once again installed north of the island right next to the heron rookery. Even if the ski course had nothing to do with the problems within the heron rookery, evidence indicated that beneficial aquatic plants were being damaged and lake water quality could be affected. It was clear that enactment of legal protections and ongoing enforcement of those regulations was the only hope for the herons. Other organizations would have to enforce protection of wildlife in the area. Luckily, the DNR Department of Wildlife, Anoka County Parks and the Lino Lakes Environmental Board cared! But what should have been a simple regulatory decision, turned into a political quagmire: it took four gut wrenching years to enact permanent protection for the colony. In any case, the environment is now protected better than before. The herons are slowly rebounding. Perhaps the colony will reach large numbers again. Hopefully, wildlife will recover and flourish for enjoyment by future generations. Maybe someday, we’ll see Black-Crowned Night Herons return. Monitoring of our treasured environments could be key. I am asking interested neighbors to please help me monitor this unique environment. Please send Email to Mail@PeltierLake.Org. Here is more information. Rookery Blues - A Minnesota Conservation Volunteer magazine article about the Herons on Peltier Lake.
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This site was last updated 03/02/10
