Island Updates

field research

Wildlife Habitat & Population Measurement UVM

Post by Science Educator Chloe Tremper

Looking at habitat suitability in the field

Twenty students and two professors from the University of Vermont’s Wildlife Habitat & Population Measurement course spent this past week on Hurricane Island. Professors Allan Strong and Jed Murdoch used Hurricane as a platform to teach field methods for estimating wildlife populations and measuring habitat variables to their students. This course focused on three methods commonly used in the fields of wildlife biology and ecology: mark-recapture, point counts, and habitat suitability index measurements. 

Mark & recapture studies are used to estimate the number of individuals within a species’ population. On Hurricane, the UVM students used this method to estimate the population size of small mammals on the island, as well as determine which species were present.  During their first day on Hurricane, the students broke into four groups and set up grids with 100 traps each on different parts of the island.  The traps were opened early each morning with a sprinkling of oats and some scraps of paper towel placed in each as food and nesting materials.  The traps used were Sherman traps, which are a box-style animal trap designed for live capture of small mammals. When the students checked the traps a few hours later, students recorded whether a trap was open and empty, closed and empty, or closed with a capture inside.  For each individual small mammal that was caught, the students marked a bit of its fur with a marker so that if it was caught again later it could be identified.  As traps were checked, the students were careful to close each so that no animals would be trapped for an extended period of time.

The students also learned how to conduct bird point counts, which are useful for monitoring avian population trends.   Four locations were designated along different trails that students would go to once a day to conduct a count in their smaller groups.  At their first point they did a 30-minute point count.  To do this, the first 10 minutes at the point all birds heard or seen were recorded, the second 10 minutes only new birds that were not noted during the first, and for the third 10 minutes only new birds again were recorded. Over their days there each group did a 30-minute point count at each of the four sites and a few 10-minute point counts at the remaining sites.

On their second to last day on the island, the students went out in the spruce-fir forest of Hurricane to measure multiple habitat variables to determine if the habitat available on Hurricane is suitable for snowshoe hares and downy woodpeckers, neither of which are known to reside on Hurricane.  However, both species habitat preferences were relevant for the purpose of learning how to implement the sampling technique.  Habitat suitability indexes are available for variety species through the USGS National Wetlands Research Center

We were sad to see this lively bunch of students leave at the end of the week but enjoyed getting to know them & appreciated the data they provided us!

Students enjoy Sunset Rock

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Cambridge School of Weston 2015

After towing around a fine-mesh net to collect plankton, students spent time looking into their microscopes trying to identify the critters wiggling around in their petri dishes. 

Learning about what it takes to be a lobsterman from Jason Day

Marilyn works with students in the intertidal between Hurricane and Two Bush Island to make sure their methods are supporting their driving question

For the second year in a row (read about last year's program here), the Cambridge School of Weston came out to Hurricane Island during the lowest tide cycle of May. Seven students and two staff joined the Hurricane community, conducting independent intertidal projects as well as two group projects focused on the quarry and on identifying marine zooplankton.

Students arrived on the island with lots of ideas for their independent projects, and after the first few days exploring Hurricane's rocky intertidal environment, they worked to modify their ideas into testable questions. 

Their projects ranged from observing parental care of dog whelks over their egg patches, to determining whether different species of hermit crabs preferred to be more or less roomy in their shell, to quantifying the range of shell colors in smooth periwinkles and whether that impacted the type of brown algae they were most often associated with. 

Low tide doesn't always wait for breakfast, so students had a few early days, heading out to their study sites by 6:30am! Doing field work in the intertidal can also be challenging because there is just about an hour-long window of time to gain access to your study site before the next low-tide cycle. This meant students had to have all of their scientific gear organized, and a clear plan for their sampling strategy in order to collect the data they needed each day.

Another goal of this program was for students to learn about some of the fisheries that are core to Maine's identity. We travelled out on Vinalhaven fisherman Jason Day's lobster boat to see him haul his traps, learn about the regulations in the industry, and get a sense of the ratio of lobsters that are thrown back to 'keepers.' We also spent time talking about Maine's scallop fishery with Cait Cleaver, our director of science and research. Cait shared about the research she is coordinating to look at the effectiveness of small-scale closures in managing the scallop fishery. After learning about her project, we all helped her build spat bags, which she will deploy in the fall to collect larval scallops. If larval scallops are found in or around the closed area, these data can help Cait get a sense of whether new scallops are settling in the area.

It was a pleasuring hosting this group and I am always impressed by the observations and creative questions that students generate when they have a chance to be immersed in field work! We look forward to seeing the finished reports of the projects, and for next year's group to build on the great ideas and questions from this program!

Be sure to check out the CSW blog about their experience for more photos!

Students enjoy a great view of the sun setting across the bay

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