Wednesday, December 15, 2010

Feed the Birds

Goldfinches at feeder
You think that you love birds. Every week you pick up your binoculars and go birdwatching with others who share your interest. You have one or two birdhouses in your properties and, of course, bird feeders that you can see from your window while you drink your morning coffee. Yes, you are very much a bird lover.

But what would you think if I told you that you are probably dooming some birds to death and starvation through your gardening practices? Let us say that you decide to buy a new tree for your yard, you love the color and shape of Japanese maples and that is what you choose. Later on, you take a look at azaleas and rhododendrons and find out that there are some Chinese cultivars which you find extremely attractive. You bypass the native varieties and choose one of those.

These innocent actions have deplorable consequences for the birds that visit your yard. Birds have no use for those foreign plants. Well, you say, “I have seen them use those branches for nests, what could be wrong with such plants?”

Until just a year ago I would have thought exactly the same. I didn’t know the bad consequences of using non-native plants as long as they weren’t invasive. But reading a book by Doug Tallamy (Bringing Nature Home) opened my eyes to a whole new perspective and a new appreciation of how food chains work, not just in nature preserves and remote parks but in our own backyards.

A nutritious caterpillar feeding on native wild ginger
Numerous insects are adapted to native plants and find your Japanese maple and alien azalea totally inedible. So what? Who needs insects, anyway? You say. –Birds need insects; that is who! Ask yourself: what do birds eat? Particularly, baby birds with their voracious appetites and fast growing bodies? They need lots of proteins; that is why their parents spend several hours a day hunting for insects, because insects are little packages of protein. If your plants are non-native there isn’t much insect protein to be found on them and the birds have to search somewhere else.

So to put it in a nutshell, each time that you plant an exotic tree or shrub you are dooming some baby bird to hunger and death. Or, if it makes you feel better, each time that you plant native plants you are helping the birds you love, perhaps even more than you do with your bird feeders.

A handsome looking native shrub, mountain laurel
Nature centers and wildflower preserves as well as some arboretums sell native plants and can provide information on them. You can also find these regional native plant lists useful: Pollinator Friendly Planting Guide. They are intended for pollinator gardens but they can apply to all wildlife.

For the area I am familiar with, the Atlantic seaboard:
Delaware Native Plants for Native Bees

And of course, the book mentioned above: Tallamy, Doug: Bringing Nature Home and the website: Bringing Nature Home

Saturday, August 07, 2010

Caterpillars are for the Birds

Have you ever seen a caterpillar hanging from a thread when you were walking through the woods? You probably have, more than once; it happens often enough that, although caterpillars are very small and not easy to see, everybody sooner or later gets a chance to see this peculiar scene.
Did you ever wonder where it was going? Certainly not up, most likely down. But, down where and for what reason?
Many caterpillars feed high on the canopy, devouring tender leaves and growing very fast. After they are done growing they start getting ready for the big transformation, called metamorphosis, which will turn the rather shapeless, wormy thing into a winged marvel, a moth.

Where you find a caterpillar there may be hundreds or thousands, all of them gleefully feeding on the same tree. Look up at the tree’s foliage above your head; there doesn’t seem to be much damage and this is very fortunate. Part of the reason is that there are many hungry creatures who regard the caterpillars as very tasty and very nutritious morsels of food. Among them you can count some of your most beloved birds, warblers, wrens, sparrows. You see them fleeting about and they may be picking up some of your caterpillar’s brothers and sisters. They will be taking them to their growing brood and ramming them down their hungry throats.
Let us get back to our question: where is the caterpillar going? It may be looking for a secluded place in the leaf litter, safe from winged predators (although not entirely safe for there are other hungry creatures in the soil too). Once on the ground it probably won’t go very far. In most cases it tries to find some leaf litter and it proceeds to bury itself in it. There it will begin spinning a cocoon using a special kind of saliva that changes into silk, strong and supple, as soon as it gets in touch with air.

It may proceed to undergo a big transformation in just one or two weeks to become an adult moth, or if it is the end of the season, it will wait until next year; hunkering down through a long and cold winter and will emerge only when the trees are already leafing out.

During that time it grows wings and legs and antennae and becomes a pretty moth ready to find a mate and to start the cycle all over again. If it is a female it will lay eggs after searching very diligently for the same kind of trees where it fed as a caterpillar.
Most caterpillars are very particular about their food; they can feed only on one kind of tree or perhaps a handful of related trees, for instance, only sugar maples or only several varieties of maples, but not oaks or ash trees. Others will choose only oaks or ash trees. They are so particular that many of the ornamental trees brought from overseas for their beautiful foliage or interesting shape are useless to them. The indirect consequence of a landscape with only imported plants is: no caterpillars - no food for the birds. If you love birds you may want to plant native trees to ensure that birds can find food hidden in their foliage.

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Tuesday, April 06, 2010

The Living Constellations Beneath our Feet

“. . . There is some kind of electrochemical communication between the roots of the trees. Like the synapses between neurons. Each tree has ten to the fourth connections to the trees around it, and there are ten to the twelfth trees on Pandora”.

So, says Grace the scientist (Sigourney Weaver) in an effort to explain the near mystical interconnectedness of that fictional planet in the movie Avatar. Being a scientist she wouldn’t use the word “gazillion”, but that is how you can interpret those numbers, quantities so huge that they are hard to grasp.

Pandora isn’t the only planet where trees are interconnected; you need go no further than your own backyard. I am not just talking about those intangible connections between plants and their animal pollinators, and plants and their animal seed dispersers. And I am not speaking of the soil enriching organisms that fix nitrogen to the benefit of many plants. These and others are important links in the web of life; but, in addition to those, there are physical, intimate, direct connections between plants and certain kinds of fungi. Moreover these fungi can establish connections between the roots of different plants. These extraordinary organisms are called mycorrhizae (or if you prefer mycorrhizas). The word mycorrhiza comes from two Greek words, myco, meaning fungus (fungi in plural), and rhiza, meaning root.

Take a look at mushrooms, those delicious morels or boletus or the deadly Amanita; you see them scattered through the forest. They look like a very small component of the plant community compared to the trees that tower over your head. Each of those mushrooms is a “fruiting body”, similar to a fruit, except that it produces spores rather than seeds. The mushrooms are the visible parts of a very large organism buried underground and called a fungus. Imagine an apple tree where only the apples are visible sprouting above the ground while the whole tree is spreading its branches underground. Such an “apple tree”, the main part of the fungus, is a very peculiar kind of organism, not as solid as a regular tree; instead it is made of a very intricate web of thin threads spreading out and connecting with themselves again and again when they meet, like a huge tridimensional spider web. They also link with the roots of trees, wrapping around them and penetrating their bark.

Fortunately, mycorrhizae are beneficial fungi which do no harm to plants; instead they establish a partnership with them. With their numerous threadlike tendrils they absorb water and mineral nutrients from the soil more efficiently than roots; so they can transfer these to the plants. In return, they get the sugars and vitamins that the plants synthesize thanks to their chlorophyll and with the help of the sun. It is a cooperative venture that benefits both partners.

Other mycorrhizae never see the light of day; they produce their spores underground and don’t form mushrooms; as a consequence, most of us are totally unaware of their existence. They are perhaps more abundant and more important to the life of the plant communities than the ones that produce mushrooms. Some of them penetrate the very cells of roots establishing an even more intimate connection with their partners.

Some members of the vegetable kingdom don’t require this kind of help. But it is estimated that at least eighty per cent of all plants are dependent on or benefit in some degree from mycorrhizal associations. It is a very ancient contract between plants and fungi, at least 400 million year old existing long before there were dinosaurs roaming the planet. It is possible that the partnership is even older and that it was established when the first pioneer plants left the water and climbed on land, around 425 million years ago.

You may think at this point: “very interesting, but how does it compare with the planetary network in Pandora?” This is what I am getting to. All these hair-like tendrils are capable of recognizing the members of their own clone and also those of closely related clones when they come in contact. They fuse when they meet, to the point that they become like one. Thus they connect among themselves and they reach out to the roots of trees, not just one tree but several. They do it again and again, forming countless links. This is the “Wood Wide Web”, so called by those who study these relationships. The bridges they form are capable of carrying water and minerals and even other nutrients not just from fungus to plant and vice versa, but also from tree to tree. Thus a fir tree connects to another fir tree and also links to the birch tree beyond them. When you walk in your vegetable garden, little do you know that the leek is talking to the carrot using the unseen web right under your feet!

A field that gets plowed over every year and is cultivated with annual crops has to start from scratch building this network every year, but a forest possesses a network perhaps as old as its oldest tree. Thus, the majestic old tree, surrounded by younger ones becomes a hub, from which the fungal network radiates in all directions like the spokes of a wheel maintaining continuous communication among all its parts. It makes you think of “Home tree” in planet Pandora or of a wise old elephant matriarch ensuring the safety of its herd.

But it is really the mycorrhizae that are the stewards of the forest. They seem to sense where the pressing needs of a plant are and from where they can borrow. In the spring, when the birches are leafless, the mycorrhizae take nourishment from the firs and carry it to them. Later on, when the leaves of birches cast shadow over the fir trees and these need some food the web reverses its flow, providing nutrients to firs taken from the birch.

“That is more connections than the human brain” explains Grace “It is a network, a global network”. And so it is with these obscure fungi; each mycorrhizal community nurtures one patch of plants and it contacts loosely with surrounding communities throughout large tracts of land. They confer resilience and stability to the forest far beyond what the trees could do by themselves.

When I ask people I meet what the word fungus means to them, the most frequent answers are “disease”, “plant damage”. The answer should be “connectivity”, “cooperation” or “healthy plant communities”.

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Squirrels, Managers of the Forest

Friday, February 05, 2010

List of articles

Alfalfa Pollination
Ants, the Unlikely Pollinators
Bees and Vitamins
Bees in the Garden
Beguinners Guide to Pollinators
Blowflies are Pollinators Too
Bumble Bees and Odor Pollution
Bumble Bees and Turtleheads
A Busy Pollinator and a Relaxed One
Buzz Pollination of Fabaceae Flowers
Crab Spiders Hiding in Goldenrod
Don't Underestimate the Native Pollinators
Flower Flies, the Great Impersonators
Flower Longhorn Beetles, the Elegant Crowd 
Globetrotting Butterflies
More Globetrotting Butterflies
Globetrotting Skippers
Hairy-legged Fly, a Gardener's Friend
Importance of Native Pollinator
Magnolias and Beetle Pollination
The Mason Wasp and the Caterpillar
Metallic Green Bees 
Monarch Butterfly, a Case of Mistaken Identity
Monarchs and their Enemies
The Midge and the Chocolate Lover
My Bees and Climate Change
Native Bees, Honey Bees and Natural Areas
Of Bees and Honey. What is Honey for?
One Bite out of Three
One Bite out of Three and Wildlife
One Bite out of Three Before Columbus
Our Friend the Elephant Mosquito
Partners and Robbers
The Pure Magnificent Green Bee
Pollinator Gardens Do Double Duty
Pollinators in Winter
Pollinators of Official State Flowers
Pollinators of the American Chestnut
Pollinators, the Night Shift
Pollinators of the Pine Barrens, NJ
Roadside Pollinator Gardens and Traffic
Robbers and Thieves 
A Sea of Blue Flowers
Sneezeweed or Helenium
Sticky Pollen 
Syrphus Fly, a Pollinator and Aphid Eater
The "Unbeetle" Beetle
Thrifty flowers
What is the Connection between Honey Bees and Almond Farming?
What is the Connection, II. Corn
You can Help Pollinators in your Own Garden

Moths as Pollinators
Black-and-yellow Lichen Moth, a Little Known Pollinator
Crambid Snout Moths
Gardening for Honorary Butterflies: Mint Moths
Hummingbird Moths. Where do They go in Winter?
Inch Worms: More Little Known Pollinators
Little Known Moth Pollinators: Seed Casebearers and Flower Moths
Metalmark Moths. More Little Known Pollinators
Noctuids, Another Family of Little Known Pollinators
Plume Moths. More Little Known Pollinators
Pollinators, the Night Shift
Yellow-collared Scape Moth
The Yucca Moth and the Yucca
Zygaenidae, More Little Known Pollinators 

Bee Houses
Bees in the Garden
Pollinators in Winter

Don't Kill Your Friends
Food for Wildlife
Ladybugs, Praying Mantis and Other So-called Beneficials. Are They?
Lawns for Pollinators, Grass Companions
Lawn for Pollinators. Part II
Lawn for Pollinators. Part III
In Praise of Bare Spots in the Garden
Pollinator Gardens and More
Pollinator Gardens Do Double Duty
Utilities Right of Way, Native Plants
You can Help Pollinators in your Own Garden

Pollinators in Winter
Globetrotting Butterflies
More Globetrotting Butterflies
Globetrotting Skippers
Wintering Pollinators
Pollinators in Winter. Fritillaries
Hummingbird Moths. Where do they go in Winter?

Flowers, their strategies
The Life of a Flower
Bumblebees and Turtleheads
Deceitful Flowers. Lady Slipper
Only Friends Welcome Here
Maple Flowers
Flowers Schedule
Inkberry Pollination
Jack-in-the-pulpit and its Cruel Deception
Nectar: Breakfast of Champions
Nectar: Drink with a Zing?
Where Have all the Spring Beauties Gone?

Biological Interactions
Alien Invasions
The Birds and the Bees. The True Story
Bugs in the Garden. Hornworm: Friend or Foe? Friend and Foe
Food Chain in the Milkweed Patch
Goats put to Service at Pennypack
Goldenrods and their Dependent Fauna
Goldenrods Fabulous Fauna
Goldenrod Galls and their Fauna
Goldenrod Galls, the Long Stemmed Ones
Hidden Life on a Pear Tree
How Much is a Bat Worth?
Introduced Species Develop Unexpected Relationships
Invisible Bird Food in the Foliage
Ladybugs, Praying Mantis and Other So-called Beneficials. Are They?
The Living Constellations Beneath our Feet
Milkweed's Last Hooray
Milkweed's Last Hooray. Part II
Milkweeds, Monarchs and More: The Milkweed Community 
The Monarch's Breadbasket
Squirrels, Managers of the Forest
Stinging Nettle. Food for Butterflies and Food for Us
The Hornet's Nest
Turtles, Shorebirds and Us
Viburnum leaf beetle, an introduced pest
When did "Common Milkweed" Become Common?
Wildlife Food and Non-native Plants
The Year the Bears went Hungry

Caterpillars are for the Birds
Feed the Birds
Invisible Bird Food in the Foliage
“Locavore” Birds. Grow your own Birdseed
A River of Birds

Funny Larvae
Hidden Life on a Pear Tree 
Plastics are not Part of the Web of Life 
Pollinators: Too Much Light!
The Sounds of Nature
Utilities Right of Way. Native Plants
Wasps, Motherhood and Ultrasound

Bugs in the Garden. Hornworm: Friend or Foe? Friend and Foe
Goats Put to Work at Pennypack
How Much is a Bat Worth?
Ladybugs, Praying Mantis and Other So-called Beneficials. Are They?
Pollinator Gardens Do Double Duty
Syrphus Fly, a Pollinator and Aphid Eater
The Prolific Aphids
The Hornet's Nest

Defenses against enemies
A Butterfly´s flashy colors
Bees and stingers

Little stories
A Night in the Life of a Working Mother
Floral Emissaries
For the Love of Flowers
The Dancing Grasses
Dancing in the Valley of the Lilies
Official State Insects
The Poop Bug and the Golden Beetle
The Year the Bears Went Hungry
Ladybeetles, the Good Ones and the not so Good

Tuesday, February 02, 2010

Dancing in the Valley of the Lilies

The air was crystal clear in the meadow under the warm May sun, blue sky above and blue camas lilies below. That was the Mountain Dawn Farm Prairie, surrounded by trees and by more blue in the distance, the Cascade Mountains.

Many flower visitors buzzed along coming and going busily, most of them bees and bumblebees, but there were others; one in particular caught our attention. It had emerged from the ground after long winter sleep, along with numerous brothers and sisters. We called him SBF, a silly name but we all knew what we were talking about. SBF was a handsome dance fly with bright eyes, a hunch on his back, a slender abdomen and a thin, long tongue that had earned him the other name by which it is known, dagger fly. He delved deeply into flowers with his tongue and drank the nectar. He could also use his dagger for other purposes as we'll see later.

The nectar fueled his flight and he was doing a lot of flying that day. In his short life as an adult he had only one purpose, to find the girl of his dreams, seduce her with a well chosen present and make love to her. If time allowed he would find another girl of his dreams the next day. But for now he was busy searching for a wedding present that could satisfy the most demanding damsel. Midges were perhaps the best choice. He wanted one big enough to be appealing to his intended but not too heavy that he could not carry it for a certain stretch of time. He knew that at some point he would end up carrying both the prey and his beloved, so he had to make a careful choice.
When he saw a suitable one, he quickly pounced on it and stabbed it repeatedly with his dagger to subdue it and also to start preparing the delicious meal that he knew ladies willing to mate would favor.

After that he wrapped his gift with silk of his own making. Then he flew through the meadow in search of a meeting place, the equivalent of a singles bar. How do dance flies know where to congregate? I wouldn't know. But he did find a gathering with several suitors holding nuptial presents, just like the one he was carrying. He noticed with satisfaction that his gift compared favorably to most of the others. He joined the group suspended on the air, flying up and down, back and forth, holding his precious cargo on front of him, just as all the other bachelors. If you come into a cloud of them, you would think that they are dancing. That is how they got their name. More and more bachelor flies joined the ranks of dancers, all of them holding a present and all of them quivering with expectations and desire.

Meanwhile, somewhere in the same meadow a young female had emerged from the ground, the same as her brothers and had started her search. She looked very similar to the boys with one big difference, instead of a slender belly; hers was like an oval, loaded with eggs. Let us call her FBF. For those of you who are wondering about the names, SBF is a nickname, the full name being: Skinny Black Fly, so it is only appropriate that his plumper female relative be called Fat Black Fly. FBF needed protein to nourish the eggs that were her future children but she wasn't about to waste her precious energy on the search for food. She would let her lover take care of that. So she tried to make herself more seductive in order to attract the best suitor, one strong enough to provide a worthy and nutritious gift. Knowing that the males love well endowed ladies she plumped her stomach as much as she could. A little deception doesn't hurt, besides the boys were not beneath adding extra wrapping to their presents making them look bigger than they really were, so they were even. A fat belly in a female is a sign that she has a full load of mature eggs; neither he nor she knows that but they behave as if they knew it.
Off she went searching for the nearest gathering, wondering if she would find her knight in shining armor. Arriving at a meeting place, one handsome fellow caught her eye immediately, it was SBF. The gift that he was holding looked quite satisfactory so she approached him avoiding one or two overly eager fellows with their puny offerings. SBF was overjoyed when he saw her and gave her his package. She took it without ceremony and proceeded to devour the delicacy folding her wings and letting him carry her. For a few seconds the extra weight caught SBF by surprise but he quickly adjusted to it and flew some distance seeking privacy. There was no time to wait. He wanted to make love to her for as long as the meal permitted and so he did.

There isn't very much else to tell about this brief romance, other than soon FBF found the right place on the ground. It had some rich decomposing organic matter that would supply nourishment to her future babies and also warmth and shelter through the long months of winter. She laid her eggs there starting the new generation that would repeat the flower visits and the sun dance the next May.

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Friday, January 29, 2010

The prolific aphids

So, your rose bushes look lovely, loaded with blossoms and you glory on their beauty. Then, disaster strikes, almost out of nowhere an invasion of vicious sap suckers starts draining the life out of the bushes: Aphids! You engage in a losing battle, hosing them, spraying soapy water, squashing them between your fingers; you refuse to use pesticides because you see yourself as ecologically responsible, besides pesticides wouldn't do much good anyway. The trouble is that when the infestation reaches a certain point it is already too late.

This is the rose aphid (Macrosiphum), a member of the very large and very odious family Aphididae and here we have an extremely heavy infestation. There are adults and youngsters, called nymphs, struggling for a free spot where to pierce the skin of the stem and feed on the plant juices. Notice that there are two kinds of adults, wingless and winged ones. Most aphids are wingless; they are little machines devoted to feeding, growing and reproducing, nothing else; they dispense with any other activities, even sex. But when conditions get too crowded some of them grow to be winged adults and fly off in search of better feeding areas.

So, what can you do to protect your roses? Prevention and foresight are the most effective tools against this stealthy enemy. It helps to know a little about their complex life cycle. In the fall or early winter rose aphids give birth to both males and females; they mate and they lay eggs which can overwinter safely. All the adults die with the onset of cold weather and the absence of juicy fluids in the plant stems; but the eggs can survive until next spring.

The eggs are pretty tiny, dark, shiny buttons scattered along the bush stems. You will have to try really hard to see them because of their minuscule size, less than 1/16"! Ah! But, if you could eliminate them or at least reduce their numbers considerably your worries would be almost over. In the spring each egg produces one female, but what a female! It is a supermom (professionals call her a foundress). It doesn't need to mate with a male, and it produces only live born females, which in turn do nothing but produce more and more babies. Since it doesn't spend any energy searching for food and since it doesn't need males to reproduce, the numbers can grow at an accelerated rate.
The colony shown above consists of descendants of one of those supermoms, a huge clone of identical twins, all of them feeding on your prized rose bush. That is why eliminating those nearly invisible eggs would protect your bush better than any later action.

The other line of defense is the wide array of aphid enemies, which under the right circumstances can keep the aphid populations from getting out of hand. Their enemies are our friends; who are they? Ladybugs are the first to come to mind; we all know that they are the gardener's helpers. There are a few others, just as helpful or perhaps even more so. Tiny parasitic wasps that lay their eggs inside the aphids; their larvae eats the growing aphid from the inside; gruesome, but an effective pest control. Syrphid fly larvae are gluttonous aphid eaters; each one can eat a few dozen aphids in the couple of weeks that it takes to reach maturity. Lacewing larvae, with formidable jaws, can attack aphids easily. All these are considerably smaller and less conspicuous than ladybugs, perhaps this is why they usually go unnoticed but they all play important roles in the control of aphid populations.
The trouble with pesticides is that they also kill all these aphid enemies; unfortunately the restoration of their populations takes considerably longer than the build up of aphid populations. So the immediate consequences of using pesticides are good but the long term consequences are counterproductive because the enemies of aphids aren't there when needed.

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