The love-hate relationship with some caterpillars can be vexing even for a nature lover

Sue Pike Published August 18 2022

I find I have to constantly keep my knee-jerk reactions to certain insects in my garden in check.  I tend to have an us vs them mentality when it comes to insects that I find feeding upon the foliage of plants I hold near and dear to my heart.  I planted a hedgerow a number of years ago that is just starting to flourish.  In it grow a variety of native shrubs-spicebush, elderberry, chokecherry, serviceberry.  The idea is to create safe harbors and food sources for native insects and birds.  Last week two different caterpillars showed up on the serviceberries.  These two caterpillars perfectly illustrate my sometimes conflicted reaction to the insects that eat my plants-a tiger swallowtail caterpillar and some yellow-necked caterpillars (Datana ministra).

Tiger swallowtail caterpillars rest during the day in webby hammocks Sue Pike photo

Tiger swallowtail caterpillars are adorable: medium-sized plump green caterpillars with a swollen thorax (the segment right behind the head, which in this case covers the head) sporting two prominent false eye spots used to scare away would-be predators.  The flying adults are large yellow and black butterflies with the dangling tails, fairly common in this area.  There are two similar tiger swallowtails found in this area.  The range of the Eastern tiger swallowtail (Papilio glaucus) extends further south and the Canadian tiger swallowtail (Papilio canadensis) further north.  To make things more confusing, these two species hybridize in central New England-so this particular caterpillar might be a cross between the two species.  Since it is difficult to distinguish hybrids from Eastern and Canadian tiger swallowtails, I have referred to this caterpillar as a tiger swallowtail-that much I’m sure of. 

Yellow-necked caterpillars are cute in their own way-dark heads, a bright yellow segment just behind the head (hence the name), with sporty brown and yellow stripes running the length of their bodies.  But they lack those engaging cartoon eyes and, more importantly, they are very gregarious-I counted at least 50 on the serviceberry bush.  Groups of ten or more were clumped on the branch tips, actively stripping the serviceberry of its outermost leaves (unlike the low-key solitary tiger swallowtail). Later this summer they will burrow into the ground to overwinter before emerging next spring as small moths.  Instead of the delight I felt upon seeing the tiger swallowtail caterpillar I immediately began planning their demise.    

Yellow-necked caterpillars are not as ‘cute’ as tiger swallowtails and are more obvious defoliators. Large groups can quickly strip branches bare of leaves. Sue Pike photo taken at littleriverphotoworkshop

If you do a search on tiger swallowtail caterpillars you’ll find lots of interesting life-history, nothing about ‘control’ since these are not considered a pest species.  Yellow-necked caterpillars, on the other hand, are considered pests.  They can cause damage to planted fruit and shade trees, but in their natural environment, in a forest for example, they do not significantly damage their host trees.  

The purpose of my hedgerow is to provide food and shelter for native species.  Both the tiger swallowtail and the yellow-necked caterpillars are doing what comes naturally, feeding on the leaves of the trees and shrubs in my hedgerow.  Both of these species provide food for birds, predaceous bugs and parasitic flies. As I considered the fate of my yellow-necked caterpillars I realized that removing them meant removing a food source for others as well as contributing to the decline of a native insect.  I figure that if the yellow-necks feed according to plan they will defoliate just the outer branches of my serviceberry bush.   If I’m lucky some robins (robins evidently love yellow-necked caterpillars) will discover them and provide a little bit of control. But if not, my serviceberry should survive this natural pruning, and hopefully next year will support even more backyard diversity.

Hopefully my serviceberries are healthy enough to withstand these yellow-necked caterpillars! Sue Pike photo

Black bears can have a coat of many colors in Alaska

Sue Pike Published August 9, 2022

While working as a naturalist in Southeast Alaska this summer I learned so much about the vastly different flora and fauna found in the temperate rainforest that we were traveling  through.   But even more eye-opening was when I experienced wildlife common to New England in a totally different way.  One species we frequently encountered that I now see in an entirely different way is the black bear.

Brown variation of a black bear foraging on barnacles in Alaska’s Inside Passage Sue Pike photo

When you go to Alaska you expect to see brown bears (the coastal name for grizzly bears), but we saw just as many black bears. Those of us from the East Coast were not too excited by our encounters with black bears.  We were jaded. We all had stories of black bears ripping down our bird feeders or hanging out on our back porches…we were there to see the iconic Alaskan brown bears.   However, with time we began to appreciate just how wild these bears were compared to our suburban black bear neighbors.  In Alaska we watched black bears coming down to the intertidal to eat barnacles and mussels or flip up rocks to catch all the interesting crustaceans that live underneath.  This was a far cry from our bird-feeder plundering backyard bears. 

Black bears (Ursus Americanus)  are found throughout most of North America-from northern Mexico up to the treeline in Canada and Alaska.  Black bears are the smallest of North America’s native bears (black, brown/grizzly and polar), and are the only bear found in the eastern US.   East Coast black bears are usually black, but out west black bears come in a host of colors-anywhere from black to brown to blue/gray to white (the rare and elusive ‘spirit’ or Kermode bear).  In fact black bears have more coat color variation than most North American mammals!  One has to wonder what name black bears would have been given by European settlers if first encountered on the West Coast.

You can tell this isn’t a brown bear (aka grizzly in some parts) by the lack of a shoulder hump and snout shape. Sue Pike photo

The actual reason for these different color phases isn’t known but there are several plausible theories.  The darker black bears are better camouflaged in our deep East Coast woods.  Out west where their habitat includes more big open meadows, lighter colors could provide more camouflage as well as some protection from the more intense solar radiation (like wearing lighter colored clothes in the summer). We saw brown black bears in SE Alaska, a temperate rainforest where thick coniferous forests stretched from the shoreline up to the treeline, one would think the lighter color could be a liability there.   Another interesting idea posits that the brown coat color is a form of mimicry-making black bears look like their larger, more ferocious cousins, the brown/grizzly bears.  The best way to tell a grizzly from a black bear is to look for the grizzly’s telltale shoulder hump.  Black bears can also be distinguished by having a rump higher than the shoulder, a straight face profile with an often lighter muzzle and tall, somewhat prominent ears.

One of the biggest lessons I learned about black bears from my experience in Alaska was just what opportunistic feeders these animals are. Watching them smash barnacles and mussels in the intertidal and then licking them from their paws one minute, contentedly munch on salmonberries the next, then graze on coastal sedges like a deer while waiting for the salmon to run made me realize I don’t really know what they eat in my backyard besides bird food and blueberries.  According to Maine’s Department of Inland Fisheries and Wildlife “Although bears eat meat, their diet is primarily vegetarian, including early greening grasses, clover, and the buds of hardwood trees in the spring, fruits and berries in summer, and beechnuts, acorns, and hazelnuts in the fall. This diet is supplemented with insects, including ants and bees (their larvae, adults, and honey), and occasional mammals and birds. Bears are not considered efficient predators, but they are known to prey on young deer and moose in late spring, and will consume carrion. Bears are intelligent, and adapt rapidly to new food sources, including agricultural crops and food placed to attract other wildlife, such as bird feeders, and untended garbage.”  

We are slowly heading into fall, a time when bears will be bulking up for their winter-long fast.  Females in particular need to put on an enormous amount of fat to support fetal development and milk production.  So, if you haven’t done this already, keep a tight lid on garbage and bring in the bird feeders at night if you have a significant bear population in your area.  Problems between bears and humans are more likely to occur if we allow bears to become too familiar with us. While I knew this already, because we were out in the wilds with bears so much in Alaska this became more real. When walking in the woods with bears (both black and brown) we wanted them to leave when they heard us coming-not view us as a potential source of food. 

Nature News: Rare northern blazing stars found in abundance on Maine’s Kennebunk Plains

Sue Pike – 8/23/22

Northern blazing stars blooming now in the Kennebunk Plains

It’s not too late to see northern blazing stars in all of their glory.  You need to find some dry grasslands, preferably with sandy soil, and look for a spiky purple flower.  I was up visiting the Kennebunk Plains this past week looking for these beautiful flowers, a wonderful place to look for rare and unusual plants and animals.  These grasslands are home to grasshopper sparrows (endangered in Maine) and upland sandpipers (threatened in Maine).  This is the home to one of only two known populations of the endangered black racer snake. There is a big sign that tells you all about these gorgeous snakes, however (for those of you not into snakes) the chance of seeing one is virtually nil.   

The reason to go to the Kennebunk Plains to see northern blazing stars is that they occur virtually nowhere else in Maine.  Also, the Kennebunk Plains population of this plant  is thought to be the largest in the world.  Northern (aka New England) blazing stars are native to the northeastern United States, in fact they are endemic to this area-meaning they occur nowhere else in the world.   Sadly northern blazing stars are rare and protected in most of New England-they are state-listed as threatened in Maine and endangered in New Hampshire.  While northern blazing stars can be found in a variety of habitats-from grasslands, meadows, cliffs, beaches and coastal meadows, even anthropogenic (man-made or disturbed) habitats, a place like the Kennebunk Plains with its vast sandplain grasslands that are kept open by the use of controlled burns presents as ideal viewing as you can get.  

The reason to go to the Kennebunk Plains to see northern blazing stars is that they occur virtually nowhere else in Maine. Sue Pike Photo

If you are interested in the bigger picture you might want to visit the Kennebunk Plains simply for its grasslands, which are considered to be one of the rarest and most threatened natural communities in New England.  The Kennebunk Plains was formed by glacial retreat approximately 14,000 years ago.  Meltwater streams formed outwash plains composed of well-sorted sand and gravel. These sandy soils have little capacity to hold water and nutrients and so the vegetation is subject to recurring drought and fire ( Many of the plants that thrive in places like the Kennebunk Plains are therefore drought and fire-adapted.  Species like the pitch pine which have thick bark that acts as armor against fire and serotinous pine cones-a type of pine cone covered with a thick resin that needs to be melted (by fire) before the cone can open and release its seeds.  Fire also benefits the northern blazing star.  Studies have shown that following fire there is an increase in the number of flowering plants and seeds produced per flower head, as well as a decrease in the amount of seed predation by moth larvae. Fire also increased seedling establishment and growth by reducing leaf litter  (Peter Vickery, 2009). 

This particular habitat with this particular soil type isn’t restricted to the Kennebunk Plains, you can find it in the Wells Barrens, even my backyard-this is unfortunate for all the non-drought and non-fire-adapted plants I keep trying to grow there.  

I have grown blazing stars in my garden for years and years, however I haven’t been growing our native northern blazing star (Liatris novae-angliae).  Globally, there are about 45 species in genus Liatris. They are all native to North America. The blazing star you can find in most local greenhouses is Liatris spicata (Licata is the genus, spicata is the species), a species with a more southern natural distribution. This is what I grew in my garden until I began my quest to preserve local biodiversity by planting native species whenever possible.  Liatris spicata is often marketed as a native plant, but now I know to always double check by looking for the species name-in this case ‘novae-angliae’.  As a result of visiting the Kennebunk Plains while the blazing star was blooming I have a new vision for the sandy soil parts of my property-instead of changing the soil into something it’s not, I plan to embrace the glacial heritage of this land (this speaks to the Earth Science teacher in me!) and work on restoring the sandplain grassland habitat it was meant to be.