Check out my latest contribution to the bird blog 10,000 birds:
Faithful Loons and Human Lunacy
Every year there manage to be two Loons out in front of the cabin, up in Minnesota’s lake country. They nest on the same, ever-expanding semi-floating but occasionally shrinking nest over behind the point, so we can’t see the nest without going across the marsh in a canoe. It is a great place to nest, but for one small detail. Behind the embayment formed by the point is a tall bluff, the edge of an ancient river valley that passed through the area during one or more (probably a few) prior interglacials. Maybe it was a version of the Mississippi River, maybe it was a version of the Warren River, likely both. Atop the ridge, where no one will ever build cabins because it is too high up, is a grove of white pines. A good way up one of the tallest pines is an Eagle’s nest.
Every year there manage to be two eagles up there in that nest. Plus hungry offspring.
So the Loons produce, probably, two chicks. Often …
When wildebeest, such as those famous for crossing the Mara River in Tanzania during their annual migration, run into a crocodile or some other danger it is often the first time they’ve seen that particular thing. This is because most wildebeest don’t live very long so many are on their very first migration. One wonders what would happen if you killed all of the wildebeest migrating in a particular year and set new ones out on the landscape to take their place. Would the migration continue? Continue reading No Way Home→
I’m going to have more to say about this topic and this book at a later time, but I wanted to get a notice of it out for Migration Week. Bird Migration and Global Change by George W. Cox addresses the issue of impact on bird populations under conditions of global warming.
This is an authoritative and scholarly book that is totally accessible to the interested bird-oriented or climate/conservation-oriented audience. After several very important context and theory chapters, the author divides the world’s migratory birds into major categories (such as “Northern Hemisphere Land Birds: Short-distance Migrants” and “Land Birds of the Temperate Souther Hemisphere” etc. etc. and treats each group separately. Each treatment is a review of scholarly work and data, and presents arguments about the way bird populations will be affected that range from concerning to downright alarming. Yet, this is not an alarmist book, simply a fair treatment of the problem.
Each chapter will give you something to think about, some data to play with, and a list of source material in case you need more.
As part of Migration Week (inspired by this post), I’m covering migration related books (mainly having to do with birds). How Birds Migrate by Paul Kerlinger (with Illustrations by Pat Archer), Second Edition, is an affordable, up to date (2009 publication) comprehensive and intelligently written book. It is written for the general public but is not dumbed down.
The thing about bird migration is that there are many facets to the behavior. There are different kinds of birds, with respect to the nature of their flight, body size, etc (think albatross vs. hummingbird). There are many kinds of landscapes across which birds migrate (terrestrial regions of varying degrees of habitability vs. open ocean). Migrations may vary in length or even fidelity to the process, with some birds in a given population doing it, others not. And, of course, there are numerous mechanisms involved in the process, with some subset of those mechanisms being used by any given bird species.
The best way to think about migration is probably as a collection of strategies using a collection of tools by a diversity of bird species.
This book does a good job at slicing and dicing the problem of migration up into bite size bits, and presents this information with numerous case studies that personalize (or should I say, birdize) the discussion.
The book is available on the Kindle but I’m not sure I would like that version, given the importance of the excellent illustrations.
They used to hunt whooping cranes. Between that and habitat loss, the number dropped from nearly 20,0000 to a mere 1,400 during the first half of the 19th century, and continued to drop to an all time low of 15 birds in 1941.
Fifteen birds, in 1941, represented the entire species.
With considerable effort from numerous private and government agencies, in both Canada and the US, the whooping crane population has soared, bird-like, from about one tenth of one percent of their normal population to almost 2 percent of their normal population (from 15 or so, depending on which source you like1, to between 300 and 400, of which only half live in the wild) over a period of about 60 years.
One of the things that had to happen to save the cranes was teaching new chicks where to go, and this was accomplished by getting them to imprint on humans. Then, the specific human to which the bird had imprinted was attached to a lawnmower engine with a propeller on it and flown along the migration route. More or less.
As it turns out, the future of the whooping cranes was tied to a small plane. Creating a new migratory flock of whooping cranes required teaching young chicks how to migrate without the assistance of adult birds. The International Whooping Crane Recovery Team decided to use an ultralight aircraft as a teaching tool to show the young whooping cranes how to fly from western Florida to Wisconsin. The program has proven very successful and as of October 2009, there are 77 whooping cranes that follow a plane from Florida to Wisconsin and back each year.
Once the cranes were imprinted on humans they needed to undergo the crane version of dating, which involved an elaborate mating dance, with human rather than crane partners. Or at least, that’s what the crazy scientists such as Dr. George Archibald, who engaged in this … activity, insisted to be necessary.
Saving the whooping crane from extinction certainly required a great deal of effort. And dancing and flying.
You will see, occasionally, verbiage such as “whooping cranes have come back from the brink of extinction.” That’s not true. They are still very much on the brink of extinction. Although there have been efforts to split the slowly growing flock into different geographical distributions, it is still the case that the wintering grounds could all be affected by a single bad hurricane year (and we do have them now and then). And, with several states attempting to bring back crane hunting, some will surely be shot while migrating. (I assume there is no effort to bring back hunting of this species, but given the way things operate there will be collateral damages if Jeeter and Bubba are in fact allowed to legally shoot at crane-like birds).
These are the kinds of books you get if you are either a scientists studying bird migration and related issues, or a very serious bird geek. The first two can be obtained at very low prices used, but the third will set you back at least 50 bucks US$ if you want a used copy. Note the spread of publication dates. It is not the case that the oldest book is out of date in all respects: Quite the contrary. Alerstam reviews theory and ideas that have not been revisited or revised to any great degree. Also, it is interesting to see how changes in the field develop over a decade or so. In any event, I’ve labeled the books by year of publication to make it very clear that I’m not showing you hot off the press items here.
1993: Bird Migration by Thomas Alerstam is a general overview of bird migration with an excellent overarching discussion of the context in which migration has evolved followed by a focused study of nine different ecologically defined categories of birds. There is also a detailed discussion of what was known about navigation at the time of publication.
On the Wing: American Birds in Migration is a children’s book suitable for up to Middle School or thereabouts. Remarkably, this ten year old volume is actually fairly accurate and comprehensible, covering most of the major aspects of bird migration, discussion ecological patterns, mechanisms, and methods used to study the phenomenon.
It is written and illustrated by Carol Lerner, who has prodcued well over a dozen anture related books of similar (high) quality including Butterflies in the Garden and Backyard Birds of Summer. Since these books are all at least ten years old you can find them at very low prices in used bookstores (in meatspace or on line). They’re all good.