Dear HLPOA and HLSIO Supporters,
Spring is the time of year we regularly get questions about our Swimmer’s Itch Control Program and what we are doing about all the common merganser sightings on the lake. To efficiently address these questions we have added this new section, “Your Itching Questions for Dr. Blankespoor.” This section will be updated whenever new questions/answers are received and answered.
Your Itching Questions for Dr. Blankespoor – July 1, 2018 Update:
Q: Where are all the common mergansers? I haven’t seen very many on the lake this year.
A: What you are seeing on the lake this year matches well with the several bird surveys that we’ve done this spring and summer. The number of common mergansers on Higgins Lake is lower than last year and significantly lower than what we were seeing in 2015. If I were a wagering man, I’d bet that if you wanted to find a common merganser fitted with a Higgins Lake webtag, you would need to search within a 30-mile radius of Tawas, MI.
Q: Why are there fewer common mergansers on Higgins Lake this year?
A: A winning formula for reducing the number of breeding common mergansers on a lake is eliminating nesting sites combined with trapping and relocating any ducklings that happen to hatch on the lake. We have identified a couple of active nests again this year which either have recently been sealed or will be sealed in the near future.
Q: Do you still want us to report it if we see a female common merganser fly into a tree?
A: Yes. While it’s getting late in the season for hens to still be incubating eggs on their nests, we still want to investigate any holes or tree cavities that have the potential to be used as nesting sites next year. We might also be able to get our fiber optic camera pole up in the cavity to see if there’s any evidence (e.g., egg shells) of a previously active nest.
Q: How many broods and ducklings have you relocated off Higgins Lake so far?
A: As of July 1, there’s only been 1 brood of common mergansers relocated from Higgins Lake. We successfully trapped the hen and her 8 ducklings. She also happened to be the hen that we captured on her nest and fit with a GPS harness, so we were able to download all the data the unit collected. We will be presenting those data at the HLPOA annual meeting at Roscommon High School on July 14. Make sure you come!
Q: Can you give us an update on the GPS project?
A: Yes. See my answer to the question above. In my last update, I told you about the hen that we captured on her nest, which was about 45 feet high (A HUGE shout-out and thank you to Dave Andre of Andre’s Tree Service!). We put a GPS unit and harness on her and then released her, hoping that she’d go back on her nest and finish incubating her eggs. Well, that’s exactly what she did, as evidenced by us catching her and her brood of 8 ducklings last week. As I mentioned above, we will have the data from her GPS unit analyzed in a couple of weeks.
Q: Will there be any more common merganser broods on Higgins Lake this year?
A: Yes. Ice-out was much later than usual, so the entire common merganser breeding season was delayed a few weeks. We consistently found 3 breeding common merganser pairs on our weekly bird surveys this spring, so I’m expecting at least 2 more broods to come off the lake this summer.
Q: Can we expect a reduced number of swimmer’s itch cases like last year? If we do happen to get swimmer’s itch, where should we report it?
A: We can’t prevent swimmer’s itch on Higgins Lake. We explained why in our last report. However, I fully expect another summer where most people will be swimmer’s itch free just like last summer. Many areas are reporting no cases of SI so far this summer. However, if you do get a case, please report it on: www.swimmersitchsolutions.com/higginslakereportacase
Your Itching Questions for Dr. Curt Blankespoor — June 20, 2018:
Q. I know that we’ve seen a significant reduction in SI cases on Higgins Lake over the past 3 years. But will SI ever be eliminated from Higgins Lake?
A. That’s ultimately our goal. All the decades of scientific research that we’ve invested into learning as much as we can about the parasites that cause SI and the hosts that carry SI are definitely paying dividends today. The extremely successful strategies that we are currently using in our SI control program are a direct result of the knowledge we’ve gained from all those years of research. But we aren’t resting on our laurels or our successes. Scientific research is the key to even more effective and affordable SI control strategies for the future. In fact, we are conducting a couple of very promising and exciting research projects this summer on Higgins Lake, thanks to funding from the HLSIO.
Q. Is one of those research projects putting GPS units on ducks?
A. Yes. We will be attaching a GPS unit and harness to all the hens that we capture. Thanks to the help of an alert lakefront property owner we located a common merganser nest near the West Boat Launch. With the help of Dave Andre and Andre Tree Service, we were able to capture the hen in her nest and attach one of our GPS transmitters. She was released unharmed and we will be tracking her movements before and after her brood hatches. We are continuing to search for active nests and working to seal other potential nests we have located.
Q. How big are those GPS units?
A. They are very small and very light. Come to the HLPOA annual meeting on Saturday, July 21 and I’ll show you pictures (and maybe even a short video too!)
Q. Cases of SI have been significantly reduced over the past three years on Higgins Lake but we can’t eliminate SI. Now that the water is warming up, people will start swimming in the lake and snails carrying SI become active. Where should I report cases of SI and what should I provide to help confirm it’s SI?
A. Please report all SI cases on our website. Go to www.swimmersitchsolutions.com/higginslakereportacase. Make sure you provide an email or phone number so that I can contact you if I have any questions about your report.
Q. Sorry for the repeat question, but please tell me again why we can’t eliminate SI on Higgins Lake?
A. Our program targets the major carrier of SI on Higgins Lake, common merganser broods. We are able to obtain permits to control common mergansers. The lake has been essentially merganser-free during the late spring and summer months over the past three years because of our trap and release program that has relocated nearly 200 common mergansers. But there will always be some reported cases of SI on Higgins Lake because:
1) Other ducks and birds can carry SI, including red breasted mergansers. The USFWS and DNR do not give permits to control these other protected species that can contribute to a lower level of SI.
2) Fly-throughs of common mergansers and other ducks in the fall can include highly infected first year common mergansers. We continue to be concerned that lakes like Higgins are vulnerable to SI infection in the fall.
Q. What are you doing to address the SI risks of these other duck and bird species and fall fly-throughs?
A. We have obtained a 3 year Scientific Collection Permit to study the SI risks of other duck species including red breasted merganser and bufflehead ducks. We hope to learn more about the infection levels in these duck species and their SI lifecycle on Higgins Lake. The results will help us study the potential need for control programs for other duck species. We also are continuing to consider the possible benefits of a fall harassment program.
Q. Do you have another update on your bird surveys?
A. Our latest survey on June 12 showed 1 pair of common mergansers and 1 single female on Higgins Lake. Most of the breeding hens are currently spending 20+ hours on their nest incubating their e)ggs. We continue to expect a maximum of 4 broods. We noted 3 red breasted mergansers on the east side of Treasure Island. If they continue to stay on the lake I’ll use my Scientific Collector Permit to determine their SI infection level and collect any adult worms if they are infected. We also counted 49 Canada Geese (29 adults and 21 chicks.
Q. What should I do if I suspect there is a common merganser nest on Higgins Lake.
A. The nesting season will be over in the next couple weeks. In the meantime, if you see a hen fly into a tree, or you know a location of a suspected common merganser nest, please report the information on our website at www.swimmersitchsolutions.com/higginslakereportanest.
A: Since we started working on the lake in 2015, we’ve conducted regular lake-wide bird surveys from ice-out until July 31. We go around the entire perimeter of the lake, which takes 3-4 hours, and we record the various birds and ducks we encounter. On May 18, 2018, we found16 common mergansers (4 males and 12 females) and a large mixed flock (50+) of common and red breasted mergansers near the island. Migrating individuals typically aggregate in large groups, so we believe the vast majority of the ducks we saw during this survey will not take residence on Higgins this summer. These ducks were spring fly throughs. The red breasted mergansers are protected, as our permit only allows trap and relocation of common mergansers.
On, May 26, we conducted our second lake-wide survey of 2018. As expected, the spring fly throughs had departed, including all of the red breasted mergansers. We found only 5 common mergansers (3 hens and 2 drakes) remaining on the lake.
2. Q: Do you have an estimate of the number of common merganser broods you expect to see on Higgins Lake this year?
A: That number is always difficult to predict, but the numbers should be low again this year. I’d estimate a maximum of 4.
3. Q: What do these surveys tell you about whether relocated common mergansers return to Higgins Lake.
A: We’ve always said that successfully breeding hens are expected to return to Higgins. However, if ducklings are relocated when they are less than 1 month old, we believe they won’t return to Higgins Lake. Instead, they return to the general area where they were relocated. For the third year in a row, our lake-wide bird surveys confirmed this — there are no second year birds (“teenagers”) on Higgins Lake. Once we trap and relocate any hens and their broods, the lake will essentially be free of any common mergansers again this summer. If the ducklings from last year, or from 2016, returned to Higgins Lake, they would stay the summer. The last time we saw a large number of 2nd year common mergansers staying on the lake during the summer was 2015.
4. Q: Did you band the chicks you relocated last year?
A: No. We tried to get a permit from the DNR to place plasticine bands on common merganser ducklings in 2016 but the DNR refused our permit request on the grounds that the plasticine leg bands would cause too much physical harm to the ducklings. Last year we were successful in getting a permit to use web tags (tiny self-piercing metal tags that are affixed to their toe webbing) instead of plasticine leg bands and all 55 common merganser ducklings trapped and relocated from Higgins Lake in 2017 were fitted with web tags.
5. Q: Tell how your research project to fit common mergansers with transmitters is progressing.
A: The custom made, miniature GPS units just arrived from the United Kingdom this past week. On Friday, we are making a special trip to Ohio to learn from waterfowl experts and be certifiedto fit common merganser hens with light-weight, specialized backpack harnesses that will carry the GPS units. We plan to outfit all the hens we trap on Higgins Lake this year with those GPS backpacks. They will be programmed to record GPS locations several times a day, so we hope to gain valuable information not only on common merganser nesting sites, but also on other aspects of common merganser behavior that might lead to effective long-term swimmer’s itch control strategies.
Your Itching Questions For Dr. Blankespoor – April, 2018:
A: Every spring, large numbers of common mergansers migrate north through the state on their way to their summer home, typically in Canada. The Michigan Swimmer’s Itch Partnership (MISIP) lakes throughout the state are reporting a similar large number of fly-throughs. Higgins Lake has always been a popular stop-over lake because our abundant minnow population provides easy food for hungry migrant ducks. We believe the science, data and experience demonstrate that we don’t need to be concerned about these spring fly-throughs so they don’t need to be reported. The late ice out may have compressed the fly-though time window making it seem like there are more common merganser this spring.
2. Q: Are all these common mergansers going to stay on Higgins Lake this summer?
A: No. Most of these common mergansers will leave the lake after staying only a few days. They will be replaced by new fly-throughs. A few will stay to breed. The males will leave shortly after the hens start incubating their eggs. The hens will stay on the lake to raise their broods. You have probably noticed the lake has been largely common merganser free the past three summers after the fly-throughs leave and all the broods have been captured and relocated.
3. Q: Won’t these fly-throughs infect our lake with swimmer’s itch?
A: The science, data and our past experience tell us that these common merganser fly-throughs present a very low risk of adding to the swimmer’s itch infection level in Higgins Lake. Necropsies of approximately 50 adult common mergansers lethally taken on Higgins Lake over the past 3 springs have shown about half were not infected with swimmer’s itch parasites and nearly all the rest were only lightly infected. In addition, the very cold spring waters make the snails largely inactive and not receptive to swimmer’s itch infection. In fact, after the Northpoint Fisheries spring harassment program from 2015 to 2017 chased large numbers of common mergansers into the Lyon Township section of Higgins Lake (where they were not allowed to shoot or harass common mergansers) the analysis of snails from both townships showed slightly lower infection levels in Lyon Township snails compared to those from Gerrish Township. And Lyon Township residents reported a similar significant reduction in swimmer’s itch cases as Gerrish Township. So we have strong evidence from Higgins Lake that spring harassment isn’t effective and spring fly-throughs don’t increase the risk of swimmer’s itch.
4. Q: How many broods are you projecting for Higgins Lake this year?
A: It’s always difficult to predict the number of broods on any lake in any given year. Our best guess is 6 or less in 2018.
5. Q: Why does your program focus on trap and relocation of common merganser broods?
A: Decades of research has shown that common merganser ducklings are the primary carriers of swimmer’s itch infection on northern Michigan lakes. They spend a flightless summer on the lake and become highly infected. In fact, research has shown their infection levels can be as much as 50 times higher than adults. The trap and relocation method of control targets the primary carriers of swimmer’s itch on Higgins Lake and it has a strong track record for success on other lakes. Brood ducks are relocated to waters that are free of the Stagnicola snails that are needed to cause swimmer’s itch. That’s why several other Michigan lakes are using common merganser trap and relocation as their swimmer’s itch control program of choice.
6. Q: Broods typically should start appearing on the lake beginning around June 1. If I see a common merganser hen fly into a tree, or a common merganser brood swimming on the lake, where should I report it?