My Year of Darwin 5/30/2014: Galapagos animals not so wild

 

"As the birds are so tame there, where foxes, hawks, and owls occur, we may infer that the absence of all rapacious animals at the Galapagos is not the cause of their tameness here." Charles Darwin, Voyage of the Beagle

The birds of the Galapagos are easily approachable and Darwin explains how tame and easily killed birds are - by him and by locals. Darwin observed a child knocking birds on the head with a stick as they came to drink at a well. Apparently, before the Galapagos became a penal colony, the birds were even tamer and landed on sailors. But there are predators there and man is not recognized as one of them. I don't know what the current situation is with most birds (another reason to get there) but I do know that one can closely approach the Blue-footed Boobies. Cool!  

My Year of Darwin 5/29/2014: Darwin summarizes the situation in the Galapagos

 

"But it is the circumstance that several of the islands possess their own species of the tortoise, mocking-thrush, finches, and numerous plants, these species having the same general general habits, occupying analogous situations, and obviously filling the same place in the natural economy of this archipelago, that strikes me with wonder" Charles Darwin, Voyage of the Beagle

Yes, why would be their separate, but related species, living on islands so close together? If you were a creationist (and that species were created) that would mean each island required a series of creations (no wonder He needed a break). I doubt very much, even so early in Darwin's career, that we was of such a mind set. More likely, he was already thinking they evolved. But how? 

Bling for a falcon

Took a group of students out to band two Peregrine Falcon chicks today near Pittston, PA. Peregrine Falcons largely disappeared from the eastern US but made a slow recovery since the 1970's. The decline was largely caused by exposure to the insecticide DDT and exposure to heavy metals, notably cadmium. Since the Clean Air Act and the banning of DDT in the US and Canada, Peregrine Falcons have been and are still increasing. 

Man-made structure have been key in recovery and I have seen nests on bridges and buildings but cliffs are the natural nesting habitat for this species. Today's trip was to a cliff overlooking the Susquehanna River giving us a beautiful view of the valley. 

The amazing recovery of the Peregrine Falcon has been due to environmental regulation and a host of dedicated citizens and scientists working hard for several decades. We put aluminum bands on them so we can recognize individuals. Sounds like a small thing but this helps us to understand how birds move to new and old areas, how long they live, their health and many other aspects of their life that would remain a mystery if we couldn't band birds. 

Here are some pictures of the site, the birds, and the process. 

Greg, a Wilkes graduate, goes dangling over the side. And you thought ornithology was boring. He will be placing the falcon chicks in bags. 

Art keeps an eye on Greg below and will pull the chicks up while Greg patiently waits below. Art organizes the banding and this was his fifteenth brood that he banded this year so far. 

Art checks on the health of a male chick (I recognize him from the random feather sticking to his back). Chicks are checked for parasites of the ear, throat, cloaca, and skin.

Momma falcon keeping an eye on the process

Momma falcon sweeping by. She was amazing calm and kept perched most of the time.
Chick being checked out by Bill of the Delaware Valley Raptor Center.

Chicks are remarkably calm during the process

Megan

 
Michael
 
 
Chrissy

Kevin

Columbine

Good luck baby falcons

My Year of Darwin 5/28/2014: Darwin's Mockingbirds?

 

" My attention was first thoroughly aroused by comparing together the numerous specimens, shot by myself and several other parties on board, of the mocking-thrushes, when, to my astonishment, I discovered that all those from Clarles Island belonged to one species (Mimus trifasciatus) all from Albemarle Island to M. parvulus; and all from Hames and Chatham Islands (between which two other islands are situated, as connecting links) belonged to M. melanotis. These two latter species are closely allied, and would by some ornithologists be considered as only well-marked races or varieties; but the Mimus trifasciatus is very distinct. Unfotuntely most of the specimens of the finch tribe were minged together" Charles Darwin, Voyage of the Beagle

There were two groups groups of birds that were important to Darwin and his development of natural selection: the finches and the mockingbirds. Each of these groups were important for different reasons. The finches show how one ancestral species can evolve into different phenotypes - various shapes. By his own admission, he did not carefully document locations of finches. Mind you, he was essential an early twenty-something fresh out of college, we could probably cut him some slack. The mockingbirds show the importance of geographic separation in the formation of species. 

Hopefully banding falcon chicks today... pictures to follow

My Year of Darwin 5/27/2014: Galapagos Islands - so close yet far enough

 

"I have not as yet noticed by far the most remarkable feature in the natural history of this archipelago; it is, that the different islands to a considerable extent are inhabited by a different set of beings. My attention was first called to this fact by the Vice-Governor, Mr. Lawson, declaring that the tortoises differed from the different islands, and that he could with certainty tell from which island any one was brought. I did not for some time pay sufficient attention to this statement, and I had already partially mingled together the collections from two of the islands. I never dreamed that islands, about 50 or 60 miles apart, and most of them in sight of each other, formed precisely the same rocks, placed under a quite similar climate, rising to a nearly equal height, would have been differently tenanted; but we shall soon see that this is the case."  Charles Darwin, Voyage of the Beagle

Each of the largest islands has a set of organisms that are largely not found on the other islands. The first example presented is that the governor could identify the origin of a tortoise from the shape of the shell. But there are more as Darwin hints and I'll let him tell the rest.

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Celebrated 45th birthday yesterday. It was nice. Wife gave me the Game of Thrones book series. 

My Year of Darwin 5/26/2014: No respect for the marine iguana

 

"It is extremely common on all the islands throughout the group, and lives exclusively on the rocky sea-beaches, being never found, at least I never saw one, even ten yards in-shore. It is a hideous-looking creature, of a dirty black colour, stupid, and sluggish in its movements."

One of his shipmates tied a stone to one and held it underwater for over an hour and it was still alive. They live on sea lettuce (Ulva) , which isn't bad at all. 

animals.nationalgeographic.com

My Year of Darwin 5/25/2014: Giddee-up tortoise

 

"I frequently got on their backs, and then giving a few raps on the hinder parts of their shells, they would rise up and walk away;- but I found it very difficult to keep my balance."

I do love thinking about the old Darwin, in his dotage, riding a tortoise but that's that the way it happened. It was a mid-20 year old Darwin that climbed mountains, survived sub-freezing nights under the stars, and cutthroats on the road.

Here are some great pics I found of Darwin and others riding tortoises. They're all, of course, t-shirts you can buy 

Rain stops cuteness ensues: woodchuck

My Year of Darwin 5/24/2014: Mmmm... pass the tortoise bladder

 

Not sure what's up with the crazy fonts. Frustrating. 

"When the tortoise arrives at the spring, quite regardless of any spectator, he buries his head in the water above his eyes, and greedily swallows great mouthfuls, at the rate of about  ten in a minute. The inhabitants say each animal stays three or four days in the neighbourhood of the water, and then returns to the lower country; but they differed respecting the frequency of these visits. The animal probably regulates them according the nature of the food on which it has lived... 

I believe it is well ascertained that the bladder of the frog acts as a reservoir for the moisture necessary to its existence: such seems to the the case with the tortoise. FOr some time after a visit to the springs, their urinary bladders are distended with fluid, which is said gradually to decrease in volume, and to become less pure. The inhabitants, when walking in the lower district, and overcome with thirst, often take advantage of this circumstance, and drink the contents of the bladder if full; in one I saw killed, the fluid was quite limpid, and had only a very slightly bitter taste. The inhabitants, however, always first drink the water in the pericardium, which is described as being best."  Charles Darwin, Voyage of the Beagle

I don't often drink from the body parts of a dead tortoise, but when I do, I drink from the sac that surrounds the heart. 

Wilkes University Tree Swallow nest update

STOP THE PRESS! 

Our box now has six shiny white eggs. Are they all from the female that is residing in the box? Most likely. Do Tree Swallows practice egg dumping (a female lays an egg in another nest - essentially a form of brood parasitism) - I don't know.

My Year of Darwin 5/23/2014: Darwin the biogeographer

 

"We shall hereafter see this law of aquatic forms, whether marine or fresh water, being less peculiar at any given point of the earth's surface than the terrestrial forms of the same classes, strikingly illustrated in the shells, and in a lesser degree in the insects of this archipelago."  Charles Darwin, Voyage of the Beagle

What Darwin is saying is that aquatic organisms are wide-ranging, such that one finds a marine species over the coastline of an entire continent. Terrestrial organisms, however, are more peculiar- those species are found in a particular valley or land formation. 

Darwin is known by many things to many people. Until now, Darwin is mostly a geologist, to a lesser extent a sociologist (although a good sociologist might scoff at that assertion) and to a lesser extent an ecologist. And now we can add a biogeographer to the list. 
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Was scheduled to go in the field today but only two people want to go out and it may just rain. May go see Godzilla at 1. 

My Year of Darwin 5/22/2014: Maybe... just maybe... evolution

 

"One might really fancy that from an original paucity of birds in this archipelago, one species had been taken and modified for different ends"  Charles Darwin, Voyage of the Beagle

So phylogenetics tells us that this scenario is most likely true; a population of finches composed of a single species flew out to the Galapagos and speciated into twelve or thirteen new species. Interesting that Darwin chose the phrase "had been taken" and not just "flew" or "found their way". Wish we could ask. 

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Rain today so not field work. Staying home and working on a poster for the joint Wilson Ornithological Society - Association of Field Ornithologist meeting. Wish I could find that data from 2004!  

Wishing you a great day reader. 

My Year of Darwin 5/21/2014: There's something about those finches...

 

"The most curious fact is the perfect gradation in the size of the beaks in the different species of Geospiza, from one as large as that of a hawfinch to that of a chaffinch, and (if Mr. Gould is right in including his sub-group, Certhidea, in the main group) even to that of a warbler. The largest beak in the genus Geospiza is shown above in Fig.1, and the smallest in Fig. 3; but instead of there being only one intermediate species , which a beak of the size shown in Fig 2, there are no less than six species with insensibly graduated beaks"  Charles Darwin, Voyage of the Beagle

A day of ecologizing in the Poconos

Wilkes University owns a bit of property outside Blakeslee, PA along the western edge of the Pocono area. Here are the highlights from today:

Field crew processing a Red-eyed Vireo

Gaywings (Polygala paucifolia)

Painted Trillium

Blackburnian Warbler

Ovenbird (from last week but the same site)

Red-eyed Vireo

Black Bears - last year's cubs?

Field Crew love! 

My Year of Darwin 5/20/2014: The finches

 

"The remaining land-birds form a most singular group of finches, related to each other in the structure of their beaks, short tails, form of body plumage: there are thirteen species which Mr. Gould has divided into four sub-groups. All these species are peculiar to this archipelago; and so is the whole group, with the exception of one off the sub-group Cactornis, lately brought from the Bow Island in the Low Archipelago."  Charles Darwin, Voyage of the Beagle

http://people.rit.edu/rhrsbi/GalapagosPages/SlideShow/SlidePages/Darwin's%20Finches.html