The Heart of Purple Martins

The Heart of Purple Martins
Shared by Heather Gallagher
Naturalist
heather.gallagher@nashville.gov
Photos courtesy Graham Gerdeman

As you have heard by now,  it has been a banner bird year at the Nature Center. The bluebirds, barn swallows and other insect eaters are visible and plentiful, especially if you choose to view them from the comfort of a rocking chair on the back porch.

And the martins-oh the purple martins! I have documented a minimum of 11 pairs and over 40 young at our site. But let's back up.

As a federally-licensed bird bander, I check our gourds weekly beginning in mid-May, each one yielding more nests, then more eggs, then more young.

Gourd with 6 beautiful eggs.

• By May 27, I counted 32 eggs in 11 gourds. 
• By June 2, there were 46 eggs. 
• The next week eggs had begun to hatch, and I counted 29 young.  

Babies, probably around 2 days old.

Young martins display no feathers. They are all about food, and have large beaks to show for it. As they age, feathers will begin to develop in the form of pins that serve as protection for the feathers.  

Our study at the Nature Center is two-fold: we participate in the Purple Martin Conservation Association's Monitoring Project as well as the Purple Martin Banding Project through the BIRD program. Documentation of nests, eggs and young is reported to PMCA yearly, while the BIRD program info is submitted to the USGS Bird Banding Laboratory in Maryland. 

The emergence of pin feathers is an indication that the birds are at the age to be banded, around 16-20 days. Believe it or not, the band will not fit correctly until the baby martin's leg is SMALL enough for it. 

Due to the close proximity of the nests, I decided on one date to band all babies, choosing the date that babies would be in that 16-20 day old window. The gourd rack was lowered, and staff removed babies one nest at a time.

Babies ready to be banded!

 As Master Bander Laura Cook, our BIRD program coordinator, recorded band numbers, I banded each baby.

Pliers are specially adapted to securely and safely close bands.

The band can turn comfortably, just like my wedding band!

After applying bands to the left leg, Master Bird Bander Sandy Bivens returned nestlings to their proper gourds. When all birds are banded, we hoisted the gourd rack back into position, and the adults returned with food in less than a minute. 

This week has been extra interesting around the martin gourds, as a hawk has been checking out the fledglings taking their first flight. 

Hawks are one of the many predators that threaten martins.

Our martins will leave soon, gathering at a roost before heading to Central and South America. Yes--they leave Tennessee over the winter, returning next March to begin again.

Now the roost is most curious: in Nashville, Purple Martins will gather by the thousands--maybe even hundreds of thousands--in downtown Nashville around the river. So when my husband shared that Heart would be playing at Ascend last August, I jumped at the chance.

And I was rewarded! While everyone was jamming to Ann and Nancy Wilson, I was looking skyward, amazed at these incredible birds as they spiraled above the Cumberland. There must have been 30,000 martins!

Purple Martins have definitely stolen my Heart!

Creek Exploration 101

Creek Exploration 101

shared by Naturalist Rachel Anderson

rachel.anderson@nashville.gov

photos credit Rachel Anderson

With the warm, humid days here to stay for a while, it’s definitely a great time to head to a nearby creek to cool off and have fun.  For many, it’s enough to feel the cool water on your feet, let the kids splash and build dams, maybe watch a leaf boat float along lazily.

Boats made of all natural materials can be fun to float down the creek

But the naturalist in me suggests another exciting idea – look a little closer, delve a little deeper, and discover what other animals (besides humans!) can be found in the creek.

Most people have caught crayfish and there are certainly plenty of these in our creeks.  But have you really looked closely at one?  How many legs do they have? What color are the pinchers? What other body structures do you see? What behaviors do you notice when you place it back in the water? 

It’s best to pick up crayfish right behind their front pinchers like this.

And there are other invertebrates (animals without backbones) that live in the creek and are pretty easy to find.  Gently lift a small rock and look closely at the underside.  Do you notice anything moving?  What shape is it? 

How many legs does this little creature have? Do you see the 3-prong tail at the end?

Don’t worry about naming your discovery, instead focus on what you can observe, what questions you might have, and what your discovery reminds you of! 

This interesting creature reminds me of a worm or a grub. It moves like one – shrinking and growing – but it’s white all over with an interesting ring of tentacle-like structures at one end. I wonder if that is the mouth? Is this the adult form or a larvae? 

This round insect is a water penny. Finding these indicates good stream quality, as they can only live in clean water. 

There are so many tiny creatures under these rocks, you may want to bring a clear cup for temporary viewing. A white ice-cube tray also works well.  If you gently sweep your finger across the insect on the rock, you can lift it up, then dip your finger in the water to release it into your container.

Want to find more interesting creatures? Place a net in the water, downstream of a rock where the water is moving quickly. Lift the rock and anything under may float downstream into your net!  If you rub the underside of the rock while it’s still underwater, you can dislodge tiny creatures as well.

As you pick up rocks and use nets to search, be on the lookout for vertebrate animals as well, like salamanders and snakes.  Most snakes in our river are harmless and quickly move away when disturbed. 

What do you notice about this snake we found in the creek one day?  We learned these reptiles, called queen snakes, eat crayfish because it regurgitated its meal when we caught it.  Probably a good idea to leave them be in the future!

Found a 4-legged friend? Be sure your hands stay wet when handling these sensitive salamanders.

How many different animals can you find during your exploration?  What do you wonder about them? Be sure to take pictures and videos of the animals you find, and then carefully release everything back into its habitat.  And be sure to come by the Nature Center with your questions and we can help you learn more about your discoveries!

Wildlife Encounters on the Burch Reseve

Wildlife Encounters on the Burch Reserve
Shared by Naturalist Kim Bailey
Photos courtesy Kim Bailey unless otherwise noted
kim.bailey@nashville.gov

This tunnel is  your entryway to the beautiful Burch Reserve. You never know what you will find there so put this trail on your to do list!

Walking through the tunnel at the Burch Reserve in early June, I spied a medium-sized rodent at the far end.  It ran out of the tunnel and up the hillside where it hunkered down in tall grass. Peering up through the vegetation, its mottled coat of stiff hairs and medium-length tail gave its identity away. I was thrilled to see my first living Hispid Cotton Rat (Sigmodon hispidus), not just a stuffed specimen.  Although considered common in Tennessee, these rats had never been documented in Warner Park. 

Hispid cotton rat hiding  in overgrowth on the Burch Reserve. It is facing left—see it’s pointed nose  far left near the center?

Cotton rats are in the same family as white-footed mice, voles, lemmings and hamsters. 

Hispid Cotton Rat courtesy Google images

They love grassy fields with shrubby overstory, so the Burch Reserve provides a perfect habitat for them. They make runways in the grass about 3" across, leaving little piles of shorn leaves at regular intervals. The name comes from the stiff ("hispid") hairs on their coat and the fact that they are often abundant in cotton fields. Cotton rats feed on grasses, sedges and agricultural crops, as well as insects, carcasses and the eggs and young of ground-nesting birds. In turn, coyotes, bobcats, hawks, owls and other predators feed on them. 

Cotton rats create  runs in the grass to move easily through their habitat. It takes a keen eye to notice the  3” wide trails.

It is always exciting to see something new in the Park and to add to our species inventory. Finding the cotton rat was a great beginning to our hike, but more discoveries were waiting on the trail.

As Melissa and I topped the ridge we noticed little clusters of butterflies spiraling up in what appeared to be a well-choreographed “dance”. After observing them for a few moments, we realized the butterflies were only in areas where a beam of light penetrated the canopy and illuminated the forest floor. Every now and then the butterflies (by now identified as Banded Hairstreaks) would descend and land on a leaf and then lean heavily to one side so that only one wing showed. I had never seen such behavior.  A later search of Rita Venable’s Butterflies of Tennessee taught me that the spiraling behavior was exhibited by males sparring over territory. As for the unusual angle they held upon landing, I could only surmise the males must be posing for nearby females!

This Banded Hairstreak landed and held this angled pose for long minutes before  joining  other males in sparring mid-air.

Now that our eyes were on butterflies, we noticed a Little Wood Satyr on the ground. This species rarely shows up on our butterfly counts, so we were happy that it was content to stay put as we took pictures. Little Wood Satyrs display an erratic flight just above the ground and appear very plain and brown in flight. However, when it lands you see its large eyespots.

As we began to descend the ridge, a bird dropped to the ground for a few seconds quite near us. The sunlight caught the feathers on its head, making it look almost florescent cherry! It was a Scarlet Tanager – a second year male based on his mix of red and yellow body feathers. The yellow female Scarlet Tanager was with him and we delighted in watching as she repeatedly flew to him, landed on a nearby branch and fluffed her feathers. She was clearly displaying to him, a display that we interpreted as readiness to mate. We laughed as this inexperienced male ignored her time and time again.

This second year male scarlet tanager is still in the process of changing into his adult plumage, from his yellow juvenile feathers into red adult feathers.

As we entered the field below Pickerel Pond we saw birds darting about a small fallen tree whose branches were sticking up above the tall grasses. When we got closer to the tree I was astonished to find a male Blue Grosbeak, a male Indigo Bunting and a Great Crested Flycatcher perched within a  foot or so of each other!  I cursed my decision to leave my good camera at home but vowed I would return soon to the beautiful Burch Reserve.

It’s not often you get to see a Blue Grosbeak and Indigo Bunting share the same tree! The Great Crested Flycatcher escaped before I could capture it on my iPhone.

Edwin Warner Park's Burch Reserve is open every day from dawn until 11 p.m. Dogs and running are not permitted in this very special natural area. 

Map of the Burch Reserve

Finally: Purple Martins

Finally: Purple Martins
Shared by Heather Gallagher
Naturalist
heather.gallagher@nashville.gov
photos courtesy Graham Gerdeman unless otherwise noted

I haven't lived in Nashville long--I moved here around 20 years ago. At that time, the Nature Center had just installed a Purple Martin gourd rack behind the building, and the staff hoped they would host Martins in every one of the 12 gourds.

But we didn't. For years, Martins were absent, or, if they did come, were driven away by European Starlings or Eastern Bluebirds. One year they even competed with Tree Swallows! Still, no Martins.

European Starling, a non-native competitor, and the Eastern Bluebird, a native cavity nester. 

Although a bad year for many of us, this year has been amazing for Purple Martins at the Nature Center. So I asked my friend and Nature  Center supporter Graham Gerdeman to photograph a nest check on a hot Tuesday morning in June.

Martins are cavity nesters, building their nests in holes in trees and fence posts. In the eastern US, they are found 99% in man-made housing such as metal houses or gourds.
They build nests out of straw and heavy grasses, and they place mud at the entry to the gourd. Finally, when the nest is complete, they place one final green leaf on top, kind of like the icing on the cake!

Martins will add mud to the entrance of the gourd as protection against predators

An adult male Martin adds a green leaf to his completed nest. 

Female birds are easy to distinguish from adult males: they have a white to creamy-white breast. Adult male Martins are fully black--almost purple! Females will lay several eggs; I have documented as many as 7 eggs in a clutch. When the last egg is laid, incubation begins, and the female will spend these hot, humid days keeping her eggs warm. She'll do this for a little over 2 weeks, then the first baby will hatch.

Five perfect eggs in this gourd! Martins in Warner Park have averaged between 3-7 eggs each season.

It's about 25 days until the babies leave the nest. Yes, they will fly right out of that gourd, launching themselves into the air over 15 feet above the ground.

Check back next month as we follow the life cycle of these amazing birds! 

Firefly Fancy

Firefly Fancy
shared by Melissa Donahue, Naturalist 
melissa.donahue@nashville.gov
Late May 2020

The light is fading behind the hackberry tree in the backyard.  I am sitting on my back porch with a soft head on my shoulder.  Whispering quietly, we are settling down for one of my favorite early summer activities with some of my favorite people.  The day has been warm, but the night is pleasant and not muggy.  We peer into the night with great anticipation.  We, my husband and two grandchildren and I, are looking for the first firefly of the evening. 

There are 25 species of fireflies in Tennessee with Photinus pyralsis being the most familiar.  At least 19 of these species are found in the Great Smoky Mountains.  Our plan was to be camping in the Great Smoky Mountains this year.  The main attraction this time of year is the synchronized fireflies near the Elkmont campground.  This species, Photinus carolinus, is the only species in America whose individuals can synchronize their flashing light patterns. 

Check out this video of the Smoky's synchronized fireflies

Fireflies (or lightning bugs) are not flies or true bugs, but a beetle in the family Lampyridae.  They take from one to two years to mature from larvae. A few days after mating the female lays her eggs on or just under the soil.  In 4 weeks, the larvae will emerge. In this larval stage, this insect lives underground for one to two winters and feeds on snails and smaller insects. They are avid hunters, injecting their prey with a paralytic substance before consuming it.  Most fireflies pupate underground or in rotting logs, although some attach to tree trunks and emerge in early spring or summer when the temperature and rainfall are just right. 

An adult firefly is about 2 cm long.  Different species eat different things: some eat nectar, other insects or nothing at all. Some species of fireflies feed on other fireflies—most notable is the genus Photuris, which mimics female flashes of Photinus, a closely related species, to attract and devour the males of that species.

Each species of firefly has a characteristic flash pattern. Called bioluminescence, it occurs when oxygen and the organic compound luciferin react together in the presence of the enzyme luciferase. This creates a “cold light” that uses 100% of the energy to produce light, and therefore no heat is produced.  This light is usually greenish-yellow but can be other colors, including one species that produces a bluish light. This allows the insects to flash.  The flashes help the male and female communicate, mark territory and warn away predators.  The males flash about every 5 seconds and the females flash about every two.  In most species, the female waits in the grass or on trees and shrubs while the male flies and flashes. When an attractive male appears, she will signal with a flash of her own.

photo credit Cosmos magazine

Just as the final light fades, we see our first flash.  Awed, we sit in a hushed quiet while flashes of lights rise up from the grass and bushes.  Then we grab our jars with holes in the lids and, laughing, head into the yard to catch our night lights.  We carefully observe the beetles, and then let them fly away and head to bed.

Life in the Soil

Shared by Kim Bailey
Naturalist at the Nature Center
kim.bailey@nashville.gov
Photos credit Kim Bailey unless otherwise noted

Spring is the time of year I most enjoy gardening. When the songs of migrating birds aren’t distracting me, I turn my attention to the greening trees and emerging plants and sink my hands into the soil. And being the critter lover that I am, I always look forward to the surprises that I inevitably uncover as I dig.   

Some years ago, I began to appreciate soil for what it is: a rich and varied habitat as diverse as its inhabitants. All those air spaces between the soil particles are filled with animals that range from microscopic nematodes feeding on bacteria, fungi and each other to the incredibly adaptive, shovel-pawed mole who moves through its landscape like a swimmer in water! Once I saw a mole emerge from a hole in the ground, run across the driveway, and dig a new hole in a matter of seconds. He literally disappeared before I could finish yelling “look at the mole”! I have respected the power of his front feet ever since. No photo proof of that quick encounter! 

However, over the years I have found some interesting animals that did allow me to photograph them. I have been entertained by both a crayfish and an American toad poking out of holes in the ground. 

Crayfish burrows extend deep into the soil where it is moist.

Chimneys like this are a sign that crayfish are nearby. 
Photo credit Science Photo Library via Google Images

American toads spend most of their lives on land and sometimes burrow into soil to stay moist.  

Have you ever found an obvious hole or space extending beneath the surface of the ground? I mistakenly dug this Trapdoor spider up, destroying her carefully constructed home in the process.  

Trapdoor spiders live in burrows underground. At ground level they construct a little door that is hinged with silk on one side. The door is perfectly camouflaged in the ground. The spider opens the trapdoor and waits for prey to approach.   

Lately I have come across a number of beetles.  

 

This June Beetle pupa began life as an egg laid in the soil. While in the grub stage, it fed on the roots of grasses and other plants. This stage lasted for three years! It pupated this spring and will soon emerge as an adult but stay underground until the following year. 
 

I found two different species of June Beetles (also known as June Bugs) not far from the pupa. Perhaps they recently emerged and will remain in the soil until 2021. Or are they females preparing to lay eggs? So much to learn! 

Another common encounter is the multi-legged centipede!  
 

Centipedes are often confused with millipedes but are unique in a number of ways. They have 1 pair of legs per segment vs. 2 pairs in millipedes.  Centipedes also have 2 “poison jaws” on their head which they use to paralyze their small prey. The round-bodied, slower-moving millipedes are detrivores and have no need for deadly mouth parts!   

Naturalist Rebecca Dandekar recently found this bark centipede tending her eggs in her garden.   

Clearly soil is not just a bunch of lifeless dirt! It is the matrix for life for thousands upon thousands of species. In fact, scientists estimate a billion organisms can be found in a teaspoon of soil.   

With that in mind, I can’t wait to get back to my garden and see what surprises await! 

Waiting for the Birds

Shared by Rachel Anderson
Naturalist at the Nature Center

rachel.anderson@nashville.gov

The first day Doug and I moved into our current home, I started a bird journal.  My first entry -- on August 31, 2001--there was a Blue-winged Warbler and a Black-throated green Warbler in a black locust tree. 

I now have nearly 20 years of observations written down – mostly about birds, but also about salamanders, wildflowers, butterflies, lichens … but mostly birds. 

My first red salamander was on Oct 14, 2001, but I didn’t find another one for 15 years! This beauty was discovered in Sept 2016, after flipping over an old railroad tie; photo by Rachel Anderson 

Some interesting patterns appear when you record phenology in one location over many years, and each spring my journal entries are particularly full of first arrivals. 

Spring after spring, Brown Thrashers arrive first, followed closely by the Blue-gray Gnatcatchers making their squeaky-chew-toy calls and the tail-pumping Louisiana Waterthrushes.  By the first week of April, these birds, plus Northern Parulas, are always present, while other species like Black-and-white Warblers and Blue-headed Vireos are sometimes seen, sometimes not. 

It’s always the male hummingbirds that arrive first at my feeders, usually two weeks before the females; photo courtesy Ronald Manley 

On the other hand, the earliest Rose-breasted Grosbeaks seen at my feeders have been females ; photo courtesy Graham Gerdeman

From my journal entries, I know any day now could mark the arrival of a solitary Scarlet Tanager in bold red and black, and one morning soon many, many Tennessee Warblers will suddenly appear, filling the air with their sharp, staccato song.   

For Indigo Buntings, we must wait until mid-April before getting a peek at their brilliant blue plumage; photo courtesy Deb Beazley 

And the familiar, rather haunting calls of the Yellow-billed Cuckoo won’t echo through my yard until May  

Flipping through my journal, I realize it’s a repeating series of appointments that I can’t wait to keep.  While all of my other social plans are put on hold and life seems suspended, my journal tells me not all of life is still right now.  Each day will bring a new, welcome and anticipated visitor to my home – all I have to do is open the door and go outside.