Monday, April 16, 2012

Radar Ornithology, Migration and Weather

Little do many of know, but on a good night in the spring or fall, tens of thousands of tiny songbirds are flying over you, en masse, to the next stop on their migratory journey, and yes, at night. Migratory songbirds, ranging from the diminutive Blue-gray Gnatcatcher to the ubiquitous Blue Jay, have flown thousands of miles to their breeding/non-breeding grounds (for the rest of this post, I'll be referring to spring migration, since that's the one that is kicking into gear now) for millions of years, and did so last night too.

There are enough birds flying over every night during migration to be picked up by doppler radar. Doppler radar antennae (radar, by the way, is an acronym for RAdio Detection And Ranging) send out waves of energy that are reflected by water droplets, much like how light reflects from a mirror, or sound reflects from a cave wall. These reflections are picked up by the radar antenna and provide the image that we see for storms and other meteorological occurrences, thereby giving the weatherman his data. But birds are, in part, made of water, right? By setting the doppler radar to pick up a different range of reflectance (the amount of energy reflected back at the radar antenna), we can "see" the birds that are passing over every night. And not only can we see the birds flying over, but we can measure how fast they are going by measuring the doppler effect of the radar waves, hence the name doppler radar. This has opened up a whole new field of ornithology call "Radar Ornithology", which is the study of bird migration using doppler radar.

You can see a good video of bird migration on a national scale as picked up by doppler radar here. The blue and sometimes green circles represent the birds seen within the range of the radar. Notice that near the end of the video, there are no more birds around areas in the south, indicating that the birds are moving north and that this is spring migration, when the birds are migrating back to their northern breeding grounds.

One of the most fascinating aspects of migration that doppler radar has helped to understand is how migration is not only affected, but completely shaped by weather patterns. The basics of it is that birds like traveling around cold fronts, or the boundaries of cooler air masses, and when storms happen, birds are forced down from their migratory pathway before they (remember most of these birds weigh less than an ounce) get caught in the storm; birders term this "fallout". Now, I'm still learning about this, but a great website called ebird is running a project called BirdCast, which provides predictions and reports about bird migration in relation to the weather (and of course each bird species' migratory cycle, or at what time during each migratory period they generally migrate). You can see the latest report on last week here, and the latest prediction for this week here.

In these times, migration is becoming increasingly dangerous for these birds, and as humans expand further and further into natural areas, more birds than ever are not returning to their breeding grounds, and as a result, ecosystems both in North America and the birds' tropical wintering grounds are suffering. I'll be posting more about this in the future as I'm reading a fantastic book about it by an ornithologist named Bridget Stutchbury called "Silence of the Songbirds", and will surely have more to share on this front in the future.

The cycles of nature are constantly in motion, and it's amazing what we can do with this new technology to better understand it. So, get out there, find those migrants, and maybe you'll learn something that has never been learned before. There are millions more birds to come, and endless more discoveries to be made.

Saturday, April 7, 2012

Almond Marsh Heron Rookery

If there ever was anything that one could use to get people into birds, it would be take them out into an open area where all the pretty birds are easy to find, and even more importantly, easy to observe.
I went to a place called Almond Marsh Forest Preserve today, and it fits this description perfectly. Almond Marsh is the home of an active Great Blue Heron nesting site--called a rookery--in addition to a lake, some prairie, forest, and of course marsh that house tens of bird species during their breeding seasons. The cool thing about Great Blue Herons, for those of you who don't know, is that they nest at the tops of trees and giant tripods installed by a group of local birders that I went with today called the Lake County Audubon Society. At Almond Marsh, these structures are out at the middle of the lake, which is flanked by a parking lot, so the nesting herons are super-easy to see with binoculars or a spotting scope. This makes it easy to get a peak into the everyday lives of the birds in the process of raising young, and it's an amazing experience to watch from when the birds are incubating, like they were today, to when the young herons are just about ready to leave the nest.
A Great Blue Heron. Image credit Wikipedia
In addition to the herons, there were a bunch of duck species (family Anatidae) that were quite easily seen this morning. First off, there was the ubiquitous Mallard .
male Gadwall. Photo Credit Wikipedia
male Wood Duck. Photo credit Wikipedia 
Then, there was a related but lesser known species called a Gadwall. I also saw numerous Wood Ducks, another striking bird that you can find in parks and streams even in the city. American Wigeons, a species I'm particularly interested in, were present in fairly good numbers. American Wigeons are kind of oddballs as far as dabbling ducks go. For example, Wigeons are regularly kleptoparasitic, meaning they pirate food from nearby animals who are also hunting. The victims of this kind of parasitism are often diving ducks or American Coots (which were also at Almond Marsh) who put in more effort than just tipping over (dabbling) to find food. They also graze on lawn grass, much like canada geese do, relatively often, and are at least externally morphologically different from other dabbling ducks like Mallards and Pintails. As far as genetics go, I'm not so sure, but this wikipedia article says they could potentially be in their own genus. Other than American Wigeons, I saw Blue-winged Teal, a particularly showy dabbling duck, and Ring-necked Ducks, a diving duck in the subfamily Aythyinae.

Male American Wigeon. Photo credit Wikipedia
Some more good birds we saw were Black-crowned Night-heron (my first of 2012), a nocturnal/crepuscular species of heron, Wilson's Snipe, a small and chubby shorebird that probes for invertebrates in marshes, Brown Thrasher (another first for this year), a relative of the Northern Mockingbird that mimics other birds in it's song, and some riveting Eastern Bluebirds (my third first of the year bird species).
Wilson's Snipe. Image credit wikipedia

The people in the Lake County Audubon Society are just great, and if any of you have even the slightest interest in birds and nature, I strongly encourage you to get out there on one of the saturdays before June (The Marsh is only open from 8 am till noon on Saturdays). There are some great birds out there. After getting 3 new birds for this year today, my Lake County year list is at 99 species, and my Illinois list is at 107 species. At Almond Marsh, the birding is easy, and you can see some great birds too. Maybe you'll run into me there too one day.

Friday, April 6, 2012

So I decided to make a blog...

So I decided to make a blog. I had been thinking about it for a while because of all the people I run into who are totally mystified by my lifestyle, and even more mystified about how I find all of these birds that they've never heard of. It makes sense too. Getting up at five o'clock almost every morning to observe the avian world and then going to bed at nine in the evening must be a pretty alien schedule to most teenagers, let alone people in general. Even more alien to them must by my passion for birds, and it's something I can't easily explain, but I'll make an attempt at it here.

Birds are everywhere. To the trained eye or ear, one can find (by chance) all sorts of species in every tree one walks by. This makes birds the perfect subjects for the average teenager--or person--to study. But then there's the experience of bird-watching. Birds are incredibly beautiful, both in voice and appearance, and are incredibly complicated. To figure out a birds behavior, or evolution, or even identity can be a intellectual challenge, and depending on the species, a physical one too. When you see a bird as strikingly beautiful as a Black-throated Blue Warbler in real life, something you've never heard of or seen before, the natural response is to want to learn more. You just made a discovery, and you want to know more. When you do learn more, you realize that that individual probably flew hundreds of miles last night (providing that this is in the spring), and if the weather permits, will fly hundreds more tonight on it's way back to it's breeding grounds. Even more amazing is that in this bird's family—the wood-warblers—there are more than 30 other species that can be just as strikingly beautiful; birds like the Blackburnian Warbler, or the Magnolia Warbler. A great man named Neil DeGrasse Tyson once said “Ignorance is the seduction of science”, which means the simplest explanation that most scientists would have for their love of science would be that they love discovering new things. This is exactly what bird-watching is. It provides a playing field for endless discovery (since there are always more birds to see, and more to learn about those birds), and I think that's pretty epic.
A male Black-throated Blue Warbler. Image Credit Wikipedia
So this is my blog. The one thing that convinced me to get a blog and start writing was a speech Amber Naslund gave, wherein she spoke about the advantages of blogging. I figured that if certain employers, especially those who pay you to think up brand new ideas, like to see your ideas on places like blogs, then I might as well cover my bases and start now, after all, I do like to write. It's also a nice perk to be able practice my writing skills, and hey, maybe I'll get one of you interested in birds.