Albany, NY: Recently, a friend out in Rensselaer County grabbed my arm and said “don’t you dare release your rehabilitated (orphan) rabbits out here—The Fisher will get them!” She went on to describe an animal so mean and vicious that no other mammal would be safe around them. And so, though I haven’t ever met a fisher, I got an idea of the reputation that precedes them.
It turns out that fishers are a member of the weasel family. They belong to Order Carnivora, Family Mustelidae and are known as Martes pennant. They are chocolate brown sleek mammals with long thick tails. The female is about the size of a housecat with a very narrow face, while the male is twice that size with a fuller face. They weigh about 11 pounds. They are not related to cats and they don’t fish and so it is a mystery why they were originally called fisher cats by settlers in the new world. Some think that is because they reminded Europeans of the pole cats back home.
They are quick and nimble tree climbers and when it is cold they will go into the ground, often usurping the nest of another animal. In fact, as a fisher climbs into a rabbit burrow, he will happily eat the rabbit and then snooze in his new home. In nicer weather, they choose tree holes for their homes; this is where a female fisher will give birth to 2 or 3 kits per season. She will look for a tree hole in which she is a tight fit, to house herself and her babies. Her home will not be large enough for her male mate to cohabit; this may prevent the kits from being mauled by the male. The mother fisher will also move the kits during their infancy to a new tree, despite the dangerousness posed to the vulnerable kits. Nobody is very sure why they do this, though it could reflect their struggles with fleas and other parasites in the trees.
Fishers have a weird and unique reproduction which demands they mate in March or April, after which the fertilized egg just floats in the mom until the following January, at which point delayed implantation in the lining of the uterus occurs and the fetus develops normally for a March birth. A week after giving birth, they mate again.
Thus began the lecture on fishers was given by Scott LaPoint, a student of our old friend Roland Kays (the NY State Mammologist) at the May SPB vegetarian dinner at the First Presbyterian Church. Scott travelled from Germany to come study the wildlife here in the States; he performed his fieldwork in the US and his analysis in Germany. His work on fishers has been supported by Universitat Konstanz, the National Science Foundation, the New York State Museum and the Max Planck Institut for Orthologie. In addition to doing the science, he is educating the public about fishers and his recent observations in the field.
American settlers have a long exploitative history with fishers. In colonial times, fisher ranged from Tennessee through all of Canada, California, and Washington State. From 1600-1900, logging and hunting were the main occupations in NY State and consequently forest cover dramatically declined as the whole state was logged over. The number of fishers, a forest animal, plummeted so that by the 1920’s their populations were at an all time low, and the price of a fisher pelt shot up to $100.
Since then, there has been dramatic reforestation of New York State, up to 75% cover. The agricultural boom across the state preserved open land. Additionally, conservation laws banned trapping for fishers in 1936. In 1970, 40 fishers were reintroduced in Ulster County. There were similar reintroductions in various other parts of the country as well. We were fortunate, for though the fishers are still listed as an endangered species in California, and not doing well in Oregon or Washington, here in New York State, they have flourished to such an extent that trapping is again legal.
Though fishers were believed to need big forest territories to be viable, it turns out they are adaptable animals and are turning up in cities; the Albany Pine Bush has a dramatic urban/wildlife interface and so it was a great place to conduct a study. The researchers intended to compare Albany Pine Bush fisher behavior with the ways of Grafton Park fishers, who are forest dwellers. They had state of the art animal collars with GPS, triaxial accelerometers which measure motion, and pingers which emit a high frequency sound that the fisher can hear. It turned out to be very challenging to track the fifteen Grafton animals in the long tracts of land, and they even used planes to find them. In the Pine Bush however, they were successful with motion sensor cameras and radio tracking.
What they observed was that the fishers are a very nocturnal species. Their peak activity is between 7pm and 3 am. They travel FIVE MILES A NIGHT in very complicated paths involving lots of loops.
An important find was that the fishers do use the culverts below the roads to safely cross them. This is a great strategy but hampered by the times the culverts get blocked up; and so maintaining these safe crossing and adding additional ones is critical to these animals surviving the urbanscape.
Their night journeys are to catch game; they eat small field mice, chipmunks, voles, moles, gray squirrel and opossum. They will eat deer carcasses, and they like wild grasses as well as other plants. They are the only predator to feed on porcupine, as they have figured out how to attack the belly in an effective strike. However, despite the fears of the public, so far we have no confirmed reports of fishers eating cats.
The adult fishers have no predators upon them to worry about—making them one of the top carnivores in the Pine Bush. Their kits are vulnerable to predation however. They are thought to be solitary hunters, coming together for mating and then parting ways. However, Scott observed some cooperative fisher behavior – travelling together and watching over each other during feeding on a kill. Some sneaky fishers helped other fishers remove their collars! The researchers noticed lots of variation in fisher personality.
Fishers also display strategy: they can’t eat all their game in one sitting because of their small stomachs. So they will hide it. For porcupines, they will prop one up so that it looks alive and they can come back to finish their meal later.
To test different degrees of curiosity and daring in fishers, Scott and Roland, set up a foreign object in fisher territory, near cameras. It was a pink flamingo drenched in orange extract. Indeed, fishers had different reactions. One fisher took a minute to go bite it and run, while another fisher just approached and ran. As yet, we can conclude that fishers have differences in how they approach a citrus scented plastic flamingo, and by extension, different levels of curiosity or caution. The researchers dream of being able to gather enough data to average out characteristics of fishers who live close to cities versus attributes of fishers in the wilderness, in order to be able to compare.
This is a little video of fishers approaching the flamingo!
http://video.nytimes.com/video/2011/05/06/science/
100000000807480/fisher-behavior.html
Scott LaPoint has been studying fishers for over three years. His work has established that the little populations of fishers in the Albany Pine Bush:
1) Numbers about 12.
2) Is nocturnal. This protects them as they are safer to move close to people and traffic at night. (In the wilderness they have a lot of nighttime activity but also travel and hunt by daylight.)
3) They use culverts to cross roads when they can.
4) They have “rest site plasticity,” meaning that they are willing to vary where they stay, including napping behind people’s houses.
The researchers would like to further investigate fisher behavior in different habitats and how they use each habitat to meet their needs (food, sleep, shelter, safety). They hope to study movement patterns further. They have some amazing maps of fisher movement in the Pine Bush generated by the GPS collars. It would be interesting to see the differences these journeys have with those travelled by fisher in larger, more isolate habitats.
Many thanks to Scott for all his work – including long days of tracking fisher in the snow. Much of the information he generated confirms generations of observation by the trappers of New York State. But his work also establishes that fisher and other mammals will use underpasses to cross the road. Wildlife underpasses and overpasses, to safeguard passage across 155, Washington Ave Extension and I-90, are critical for wildlife in the area. Perhaps the National Science Foundation can offer a grant to build and study this important solution to the highway massacre of mammals whose home are in this rare Pine Barrens. – by Grace Nichols
Published in July/August Save the Pine Bush Newsletter
