Naturespeak A naturalist's view of the world

September 8, 2008

Priceless Little Gem ? Part Twa

Filed under: Uncategorized — wykes @ 7:50 pm

? I thought that you might like to know. That?s why I returned to that Ruby-throated Hummingbird nest once again ? you know the one I showed you last month. It was a late brooding female in a Sycamore Tree and I was curious about her success.

? In case you don?t know what I?m talking about you: A) are completely typical of ?my? reader base or B) you didn?t read the earlier ?Priceless Little Gem? entries. If you are an ?A?, please hold on for a moment while I advise the ?B?s? that they might want to catch up on things and look at the earlier August entries. Anyway, I thought you both would like to know that the little hummers have hatched and they appear to be in good shape. The ?gem? has produced a pair of ?gems.?

? I find nearly everything about these micro creatures fascinating, but I have to admit that this particular nest has been a pain in the neck. It?s cryptic location and height requires the observer to stand in one particular place and gaze skyward for an extended period of time. I managed to watch the nest for about 45 minutes but found that my fascination factor was gradually taken over by my fractured neck factor. ?I had to quit observing before I really wanted to and devote the rest of the day to the intent study of ground fauna. ?I couldn?t review my pictures until the next day.

? Well, my photo record is less than spectacular, but I?ve selected a few.? Apart from the above shot, where you can see the better part of one nestling and the beak of the other, I took a few more (here with one visible?and here with two beaks in view).? Based on apparent age of these birdlets, it seems that the female may have been sitting on young when we first encountered her.? It takes 8-12 days after hatching before baby hummers can maintain their own temperatures. These guys were without motherly attendance for about 20 minutes at a time, so it is apparent they were well into self-regulation.

? Another thing that marks them as ?well along? is that they could poop on their own.? For those of us who have experienced the joy of parenting, this is a big step for any species. One of the few highlights of watching this hummingbird nest was the occasional ?moon-rise? in which a tiny feathered butt rose up over the nest edge and forcibly shot a white stream of doo a foot or so from the edge.

? ?Earlier in their nestling careers, their mom had to physically grab a little white packet (called a fecal sac?) from the southern region of each chick and take it off to the dump. In one case ?not this one -a female was observed placing these little packets in a line on a branch immediately above the nest as a fecal form of d?cor!? Others have been known to eat these poo packets (without salt or sweetener I might add).

? This Sycamore tree female returned to the nest to feed her little ones only twice during the time I was there. This would put her squarely in the average hummingbird range of about 3 feedings per hour. Her time at the nest side was brief and active.? She clung to the side and directed her beak down the throat of each young while pumping in a slurry of nectar and insect juice ? pulling her head back at a sinuous angle to pull her bill out of the gaping infant mouths. She briefly paused once the feeding was done and appraised the general surroundings before buzzing off (see here). ?

? If all goes well, and my calculations are correct, these infant hummingbirds will be ready to leave the nest in about a week and half. It takes all that time and more for the nestlings to attain their full complement of iridescent feathers. I have seen it written that hummingbirds possess more feathers per square inch than any other bird. Considering that they barely qualify for a square inch of skin to hold those feathers, I guess I?ll have to pass on the accuracy of that statement. You can?t believe everything you read ? except here in ?Naturespeak? of course.

Priceless Little Gem – Part Twa

Filed under: Uncategorized — wykes @ 7:50 pm

  I thought that you might like to know. That’s why I returned to that Ruby-throated Hummingbird nest once again – you know the one I showed you last month. It was a late brooding female in a Sycamore Tree and I was curious about her success.

  In case you don’t know what I’m talking about you: A) are completely typical of “my” reader base or B) you didn’t read the earlier “Priceless Little Gem” entries. If you are an “A”, please hold on for a moment while I advise the “B’s” that they might want to catch up on things and look at the earlier August entries. Anyway, I thought you both would like to know that the little hummers have hatched and they appear to be in good shape. The “gem” has produced a pair of “gems.”

  I find nearly everything about these micro creatures fascinating, but I have to admit that this particular nest has been a pain in the neck. It’s cryptic location and height requires the observer to stand in one particular place and gaze skyward for an extended period of time. I managed to watch the nest for about 45 minutes but found that my fascination factor was gradually taken over by my fractured neck factor.  I had to quit observing before I really wanted to and devote the rest of the day to the intent study of ground fauna.  I couldn’t review my pictures until the next day.

  Well, my photo record is less than spectacular, but I’ve selected a few.  Apart from the above shot, where you can see the better part of one nestling and the beak of the other, I took a few more (here with one visible and here with two beaks in view).  Based on apparent age of these birdlets, it seems that the female may have been sitting on young when we first encountered her.  It takes 8-12 days after hatching before baby hummers can maintain their own temperatures. These guys were without motherly attendance for about 20 minutes at a time, so it is apparent they were well into self-regulation.

  Another thing that marks them as “well along” is that they could poop on their own.  For those of us who have experienced the joy of parenting, this is a big step for any species. One of the few highlights of watching this hummingbird nest was the occasional “moon-rise” in which a tiny feathered butt rose up over the nest edge and forcibly shot a white stream of doo a foot or so from the edge.

   Earlier in their nestling careers, their mom had to physically grab a little white packet (called a fecal sac”) from the southern region of each chick and take it off to the dump. In one case –not this one -a female was observed placing these little packets in a line on a branch immediately above the nest as a fecal form of décor!  Others have been known to eat these poo packets (without salt or sweetener I might add).

  This Sycamore tree female returned to the nest to feed her little ones only twice during the time I was there. This would put her squarely in the average hummingbird range of about 3 feedings per hour. Her time at the nest side was brief and active.  She clung to the side and directed her beak down the throat of each young while pumping in a slurry of nectar and insect juice – pulling her head back at a sinuous angle to pull her bill out of the gaping infant mouths. She briefly paused once the feeding was done and appraised the general surroundings before buzzing off (see here).  

  If all goes well, and my calculations are correct, these infant hummingbirds will be ready to leave the nest in about a week and half. It takes all that time and more for the nestlings to attain their full complement of iridescent feathers. I have seen it written that hummingbirds possess more feathers per square inch than any other bird. Considering that they barely qualify for a square inch of skin to hold those feathers, I guess I’ll have to pass on the accuracy of that statement. You can’t believe everything you read – except here in “Naturespeak’ of course.

September 6, 2008

The Killer Shrew

Filed under: Uncategorized — wykes @ 8:06 pm

  Over the years, many creatures have been turned into the stuff of horror movie plots. Spiders, sharks, crocodiles, and even rats (remember Willard?) have been cast as evil forces of nature that only attack stupid people. Usually, for the sake of dramatic flare, these things have to either become gigantic or gather themselves into hordes of unimaginable proportion before they can go about their dastardly deeds. Birds of a different feather, for instance, had to flock together before Tippi Hedren considered them a threat in “The Birds.”

  In the B horror movie hey day of the 1950’s someone came to the conclusion that shrews were an untapped source of villainy. Apparently, someone read a book that said shrews had ravenous appetites and murderous ways. Such horrific promise certainly could not be overlooked.  From that kernel of an idea came a kernel of a movie called “The Killer Shrews.” The movie was released in 1959. It featured dogs dressed up as the “shrews”, a professor, a beautiful foreign chick and a crew of “other people” (you know, the ones you know will not make it to the end) who were trapped on an island full of ravenous genetically altered shrews. The two most memorable lines from that movie were “Senior, there ess a shrew in de basement,” and “don’t you even want to know about my accent?”

  I’ll give some credit to the writers of this movie. First of all, they showed remarkable restraint by supersizing these things to dog-size rather than elephant-size proportion– after all, shrews are among the tiniest of mammals, so Fido-sized is massive when that fact is considered. Secondly, when the professor explained that the escaped creatures will soon turn on each other and that all they had to do was hole up until they killed each other off, he was merely parroting scientific literature.  One such authoritative source states “if (the shrews) are not able to find food within about a 2 hour period, (they) will attack and eat each other.”  Another confidently says that shrews “are in a permanent state of raging.”  It is true that shrews can eat as much as 3 times their body weight in food every day.  They have tremendously high metabolisms. No wonder the writers felt confident with their plot line. It is very believable that a roaming band of killer shrews would still be hungry after eating everyone on the island and the horse.

  It was only a few weeks after I watched “The Killer Shrews” that a certain person in my house, who doesn’t want to be mentioned by name, was accosted by a Short-tailed Shrew (“Senior, there ees a shrew in de living room”). The tiny creature ran over her foot and thus condemned itself to death.  This certain person saw it earlier in the day and was willing to entertain my plea to let it slip quietly out the back porch door, which was left open. Unfortunately the creature failed to take the hint, performed the above act of personal space violation, and thus had to be caught in the jaws of death. 

  I introduce to you, ladies and gentlemen, that killer shrew (see above).  Short-tailed Shrews can get to be about 4 inches long, so among shrews they are relative giants (see here). Still, they are quite small and get mistaken for mice all the time.  They differ from these rodents in many ways, however.  First of all, they have pointy little snouts with pin-prick eyes and no obvious external ears.  Their short-cropped fur is velvety gray and, despite their name, their tail is quite short in comparison to the body.  Perhaps the biggest difference is their teeth. Mice have buck teeth and flat grinding molars while shrews are carnivores with 32 sharp little teeth and fang-like incisors.

  Pull down the lower lip of a dead shrew (they are much more co-operative that way) and you’ll see a hefty pair of lower incisors (see here). This type of shrew is in a group called the “red-toothed shrews” which possess colored teeth that make them look ominous. This shade is not the result of a bloody meal, it is only pigmented enamel.   There is a groove that runs between these incisors which acts as a conduit for injecting venomous saliva into their prey. Yes, short-tails are venomous.

  Located in the lower jaw, toxin glands exude a paralyzing agent that is employed to immobilize or kill prey outright. This type of shrew has been known to attack large prey such as mice, but their stock in trade is small invertebrate fare like worms, crickets and snails. A single bite from a Short-tail can immobilize a mealworm for up to 15 days. Whoa! This paralyzed food is stored for later consumption. Imagine the silent horror of seeing a pile of paralyzed snails. Those movie guys missed out on a great plot twist when they overlooked this little fact.

  Another fascinating shrew fact worth noting is that they have the ability to echo-locate.  Equipped with extremely poor vision and sense of smell, shrews send out ultra-sonic clicks to sense their environment. It’s too bad my little victim couldn’t have located the back door before it became a specimen.

  There are a good number of mammals on the planet that can echolocate, such as bats and whales, but only the European Water Shrew can share the claim to deadly spit. I definitely can see movie sequel potential here, perhaps “Taming of the Water Shrew.”

September 3, 2008

Sweet Song of Success

Filed under: Uncategorized — wykes @ 8:37 pm

  Insect music is everywhere this time of year. I could say that “the hills are alive with the sound of music,” but here on the flatlands near the Erie shore we have no real hills.  We have a few fake ones, but they don’t count. It’s more accurate to say that “the fields, trees, and bushes are alive with the sound of crickets.” I doubt that the Hollywood version of Maria Von Trapp would have been caught dead singing those words as she ran through a tangled scrub thicket.  The camera would have lost sight of her and the crickets would have stopped calling. That’s no way to start a musical. This is probably one reason that “The Sound of Crickets” never made it to the big screen. The other reason is that cricket music isn’t all that musical to our ears.

  Sure, cricket chirps can be soothing at times, or even informative (see Naturespeak: Crickemometer), but for the most part they are rather annoying. To prove my point, listen to this recording and see how long you can take it (listen to Black-horned Tree Cricket– on full volume). This is the call of the Black-horned Tree Cricket.  Although this creature is in the same family as the soothing-toned Snowy Tree Cricket, his call is more migraine inspiring than mesmerizing.

  The Black-horned head driller, er…Tree Cricket, is only about a half inch in length. Like all tree crickets he is slender and relatively pale (see picture above).  They are a secretive lot that go about their daily lives in obscurity – that is until summer is nearly extinct. Then the males begin to perform their calls with machine-like precision in order to attract potential mates. Wings lifted high up off their abdomen, the guys rub a file on one wing against a ridge on the other to create their pulsating version of a love siren.

  Just for your own edification, you might like knowing that this call is produced at a numbing rate of about 35-45 pulses per second at a level of around 4 kHz (kilohertz that hurt). Because Black-horned Tree Crickets prefer lower vegetation, they are more frequently seen than their arboreal relatives. Still, they are not easy to find.

  It took me about ten minutes to locate this male (see here) even though my ears were beginning to bleed. He stopped calling immediately upon being discovered and froze into position.  His orientation at the base of the grape leaf apparently was not accidental, however.  As he was, the curl of the leaf formed a natural sound dish that amplified his manly tones. I found another individual a few minutes later and he was situated in the same exact kind of spot (see here). This little bit of acoustical posturing makes for better projection. Projection is the way to get the babes.

  Female Tree Crickets are lured in from afar by the sound of this music.  Once the gals are close in, the males have to switch from music to food in order to keep them around.  Underneath those musical wings lies a pair of cavities filled with sweet secretions.  So-called “Honey Pots” by keen tongued entomologists, these syrup dispensers are actually called metanotal glands. They exude a high protein brew which acts as a courtship gift.  The females are induced to crawl up onto the male’s back and imbibe in the nectar.  While she laps up the ambrosia (often lingering for up to an hour), the male successfully does his “reproductive thing.”

  Ah, Music and food – the stuff of annoying romance.

September 1, 2008

Knot the End of Summer

Filed under: Uncategorized — wykes @ 7:57 pm

    Labor Day is often hailed as the last day of summer, but the actual calendar end doesn’t arrive until much later in the month. There’s no denying the presence of school supplies on the store shelves, but we’ve got plenty of “summer” left. The winds of seasonal change are blowing in from the north, however. Migrant birds are already stirring and some of the long distance travelers, such as Osprey and warblers, are already on the move.  

  One of these world travelers, a shorebird known as the Red Knot, arrived in our neck of the woods just last week (see above). It was feeding among the accumulated water plants cast upon the shore of Lake Erie at Lake Erie Metropark. The appearance of this weary traveler in S.E. Michigan is an occasion knot to be overlooked. They are rarely seen here. Knots breed in the high Arctic at such top-of-the-world places as Ellesmere Island and Siberia. The species migrates all the way to the bottom of the world to Patagonia and the Straits of Magellan and usually does so via an east coast route. Michigan is knot in this migrant’s travel guide. 

  By the way, in case you are attempting to calculate the mileage between the Arctic and the northern suburbs of the Antarctic, this is a distance of some 9,000 miles one way. Knot all of them go all the way to the end of South America, but most do.  By flying 18,000 miles annually, they can be considered as one of the champion migrants found on the planet. 

  Who knows why this bird showed up here (shoulda took a left at Moosejaw, perhaps?), but one explanation lies in the fact that it appears to be a young, and perhaps inexperienced, individual.  Counting this sighting, I have seen exactly one Red Knot in my lifetime so I can-knot make any deep comparative identification judgments. It does appear to match the guidebooks as a juvenile bird rather than a typical winter phase adult. This time of year the adults have an even gray back while this one has scalloping on the back (here, look at another view). I should also add that I did knot originally find the bird. It was spotted by an alert and very experienced birder who knows a good thing when he sees it.

   You are probably wondering at this point why this thing is called a Red Knot. If you’re knot, you should be.  Take the “red” part of the name, for instance. This bird does knot have a speck of red on it. As it turns out, both sexes of this species have robin red breasts during the breeding season (see here). They shed the fancy stuff during the off season.

  The “knot” part, now, that’s a different beast.  To be perfectly honest, I don’t think anyone really knows where that name comes from. One of the explanations states that “knot” is derived from “Knut.”  The species name, Caladris canutus, was given by Karl Linnaeus in honor of King Canutus the king of Denmark.  This guy once had the gall (or is it Gaul?) to “command the tide to keep back and not approach him.”  The sea said “not!” and the king was forced to “retire there from” to keep from getting wet.  Because this is a bird of the tide line, this seems an appropriate title.  The thing becomes strained when it is explained that Canutus’s nick-name was Knut and that it was corrupted to “Knot.”  Like the sea, I say “Knot!”

  The other likely, although still hard to accept explanation, is that the bird’s call sounds like “knot, knot, knot.”  Go to this web page (here) and click on the part that says “listen to the bird’s call” and decide for yourself.

  Unfortunately, all of this name stuff fades into obscurity when you consider that this bird has fallen onto hard times as of late. Once one of the most abundant of shorebirds, the North American population of Knots has plummeted within the past few decades. No one is sure exactly why.  Some blame this on a reduced number of horseshoe crabs upon whose eggs these migrates depend.  Fortunately, elsewhere in the world they appear to be holding their own.

  Let’s hope this youthful migrant will complete his southbound journey by summer’s true end. We wish him luck when he returns to the arctic next spring, ties the knot, and has a family of little knotlets who inherit their directional skills from their mother.

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