The Dawn Chorus

If you’re like me, you don’t have air conditioning in your house. Therefore, you’ve probably noticed the dawn chorus outside your window well before you’re fully awake. It usually begins around 30 minutes before sunrise, and continues for about 45 minutes after the sun breaks the horizon. Several theories have been proposed to explain the timing and frequency of birdsong during this early morning concert; these include foraging efficiency (it’s more efficient to sing before you can see well enough to forage, then once it’s bright enough, eat like crazy), ability to detect predators (evolution would tend to favor those individuals that could see their predators when they were singing… otherwise becoming an easy breakfast), and sound transmission (sounds should carry clearer and further in still morning air than they would in the more turbulent atmosphere characteristic of later in the day). As one of his major findings, Karl Berg discovered a correlation between eye size and time of first song for birds in a broadleaf forest in Ecuador. His findings support the idea that light levels are an important driver in the pattern of birdsong during the dawn chorus. You can download his paper here.

Last week I co-taught (along with Ben Baiser and our advisor, Julie Lockwood) the Rutgers Field Techniques course down in Tuckerton, NJ, where we assigned three field projects to three groups of students. One project was to investigate the pattern of birdsong in the dawn chorus in the Pine Barrens. The group hypothesized that birds which tend to forage in the canopy would begin singing earlier than those that foraged on the forest floor (inefficient foraging hypothesis). Those that forage primarily in the mid-story would fall somewhere between the two extremes. After two days of field recording and observing bird foraging behavior the group found a statistically significant relationship between foraging niche and time of first song. Interestingly, this relationship was the reverse of what they expected (ground-foragers began singing first, while canopy-foragers began singing the latest). While this field course was primarily intended as an exercise in how to design a field experiment to test a hypothesis, collect and analyze data, and present results, these preliminary findings provide an interesting starting point for a comparative study between a variety of habitats. The group concluded that they should collect light penetration data in order to further evaluate the difference between the New Jersey pine forest and the Ecuadorian broadleaf forest site from Berg et al. (2006).

In preparation for teaching the course, on May 25th, I used two Rode nt5 omni-directional microphones (thanks Casey!) to record the dawn chorus at the Hutcheson Memorial Forest, in Somerset NJ. I began the recording at 4:39am and recorded until just after 7:00am. The recording was made on a Marantz PMD670 compact flash recorder. Below is the entire recording in two parts, with the only edit being the removal of 27 seconds where a plane flew overhead. I hope to make more recordings, both here and elsewhere, and post them as I go. I’ll have the pine barrens recording up sometime soon as well. Enjoy listening to the dawn chorus, and testing your identification skills along the way!

Enjoy
David

Part 1. This one begins at 4:29am, so there’s a good amount of “quiet time” at the beginning, although you can hear the birds in the old field adjacent to the forest already singing. Something, a screech owl, I think, does a freakout call+bill clapping right over the recorder about 19 seconds into the recording. It repeats it again soon after, from a little farther away.

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Dawn chorus recording (Pt 1)
Hutcheson Memorial Forest, Somerset, NJ
David La Puma
Marantz PMD670
Stereo; 2 Rode nt5 microphones
Edited in Audacity 1.2.5
Converted to mp3 in iTunes 7.6.2

Part 2. This recording continues where part 1 ended, at about 6:00am.

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Dawn chorus recording (Pt 2)
Hutcheson Memorial Forest, Somerset, NJ
David La Puma
Marantz PMD670
Stereo; 2 Rode nt5 microphones
Edited in Audacity 1.2.5
Converted to mp3 in iTunes 7.6.2

Taking too long to load? want to download the mp3 file?
Here are the links:

http://woodcreeper.com/audio/DawnChorus_HMF_Pt1.mp3
http://woodcreeper.com/audio/DawnChorus_HMF_Pt2.mp3

American Woodcock




American Woodcock

Originally uploaded by woodcreeper.

With the rise in evening temperature over the last two weeks, the Woodcocks have made their presence known. A very secretive and well camouflaged resident and migrant of New Jersey, the American Woodcock blends in easily with the under-story and can go unnoticed save for its explosive flight from underfoot should you almost step on one. Eyes situated almost behind their head, they have better vision behind them than in front of them…which I guess helps see your foot!

Of course, the other time you might be fortunate enough to see a woodcock (or Timber doodle, as they’re also called) is during their elaborate nuptial display flights. We’re pretty lucky in that we have a nice wet field adjacent to the woods behind our house, and so we get a few woodcocks each year, strutting their stuff on the ground, and taking flight in a whirring, twittering display. It’s both wonderful and comical.
Last night I was able to record one bird doing his typical “Peent” call. I had positioned myself in the field just before dark, on the edge of some cedar trees so that I could “blend in” as much as someone as imposing as myself can blend into a field. Just before it got too dark to see, a woodcock came flying across the field, banked slightly toward me about 10 feet away, and coasted into the bare area of field just 5 feet away from where I was seated. I was shocked! There was a tiny little cedar tree in between the bird and myself (about 1 foot tall) and I couldn’t see the bird. I decided this was okay, because it probably couldn’t see me either…so I pointed the microphone at it and waited.

A few seconds later I heard this guttural sound that I know was the bird, but had never heard before. I’ve heard Cape Sable seaside sparrows do a little pre-song bill clapping only audible at very close distances, and this was similar in that it sounded like some kind of pre-song gurgling. Then it happened “PEENT” Aghh! I had the gain turned all the way up on my recorder and the sound was deafening in my headphones. I hadn’t expected the bird to land so close! Worse still, I couldn’t reach down to reduce the recording volume because the bird was so close…I’d just have to take it “PEENT!” Oh god, not again!

So this went on for a good 4 minutes, without the bird flying up and doing its aerial display. I think it was just a bit too cold and a bit too windy for the full ensemble. I then realized that I was picking up a rustling noise in the leaves to my right, but I dared not move. I glanced to the right with my eyes only, and noticed another Woodcock coming in. Each time the first one went “Peent”, the second one would waddle a little closer in the direction of the singer. What a funny looking bird- waddling around the field floor. Then I picked up another sound, more rustling, this time louder. A rabbit! A rabbit came hopping up; in between me and the second bird (the other bird was about 4 feet away- so the rabbit was at about 2 feet). “This is crazy” I thought. “Okay rabbit, don’t blow my cover!” The rabbit took one look at me and seemed disinterested and moved on. Woodcock number two made it within a foot of woodcock number one, and then number one exploded into the air and away over the woods. Not interested? Spooked? I have no clue. Woodcock number two kept waddling toward the spot where number one had been calling from, and within a minute of number one leaving, number two took flight in the same direction. I still don’t know what caused it, maybe I finally got into view for the birds, or maybe they were just heading off in search of better fields. Either way, no more woodcocks were heard over the next ten minutes, and at that point it was too dark to see, so I packed up my things and headed back to the house.

Unfortunately the weather has turned cold again, so I’ll have to wait for a little warm up before getting anymore impressive displays. In the meantime, I’ve made several clips of the recordings so you can check them out. There are 4 in total:
1. A segment of the “peent” vocalization, at regular speed.
2. The same recording, but incrementally slowed down to 1/2 speed, then to 1/4 speed.
3. The same recording as #1, but at 1/2 speed
4. The same recording as #1, but at 1/4 speed (you can really hear the individual notes that make up the guttural vocalization)
Recordings made with a Sennheiser ME66 shotgun mic connected to a Marantz PMD670 Compact Flash recorder

Click on the image to view full-sized
American Woodcock 'peent' American Woodcock 'Tukoo' detail
Sonograms made in the awesome and FREE program Syrinx

You gotta love the Birds of North America species accounts. This is from the American Woodcock account: Continue reading “American Woodcock”

Winter Finching

Inga, Diane, Sandra and I headed north last week in search of the winter finches that have been invading Algonquin Provincial Park in response to the bumper cone crop this winter.

This trip was steeped in significance for me; as I’m sure it was for everyone, albeit for different personal reasons. I saw my first (12) evening grosbeaks in 1996, eating from the feeders at the house of my professor during our field ornithology course. I can remember the event as if it were yesterday, which is significant when you consider how few of the others from that semester I can actually recall. Little did I know that evening grosbeak would be a bird I would wait over 10 years to see again. But how? They were absolutely abundant and pigging out! Surely as long as you put out seed- these birds would be there. I knew so little.

Our first encounter with an Evening Grosbeak was at the Spruce Bog Boardwalk Trail (actually, it was in the parking lot of the aforementioned trail). We had just arrived to the boardwalk, gotten all bundled up, rolled out of the minivan, and there- in the tree- calling. There it was, a female evening grosbeak. I fumbled for my binoculars, then my microphone, I needed to capture the bird in any way I could. I’m sure I looked silly, and the bird flew off. Moments later ,though, a gorgeous male flew in and serenaded us again. This time I was able to capture his sound and get a good look. What a handsome bird that is!

I could go on and on and bore you to death with the details of the trip- but instead I’d rather let you experience some of it for yourself. Here’s a little playlist of some of the sounds we heard, from the Evening Grosbeaks to the Red and White-winged Crossbills, to the more familiar song of the Pine Siskin, and finally some of the natural soundscapes and a really cool encounter with a bull Moose and family.

This trip could not have been as wonderful as it was, had it not been for the hospitality of The Ellis’s who put us up (and put up with us) on Thursday and Saturday night. They really are the coolest folks on earth. For more photos from our trip go ahead and click on the Evening Grosbeak above. You can get more of the scenery shots on Inga’s flickr site by clicking here, and Sandra has also posted some on her site here. If you have any questions regarding the trip, photos, or recordings, feel free to leave a comment on this thread or email me directly.

Good Birding!

Crow Mafia

I had gone out early this morning in hopes of testing out our new microphone and solid-state recorder for our Ornithology class. The usual birds were singing, Tufted Titmouse, Black-capped Chickadee, the occasional White-throated Sparrow. I picked up a Northern Cardinal singing down the trail a bit, so I walked along in an attempt to get closer. When I rounded the corner I found the cardinal perched about 30 feet in the scrubby edge of a cedar stand. I positioned the microphone toward it, noted the species, and almost immediately saw (and heard) a Great Horned Owl come bounding out of the top of a red cedar. It had been perfectly camouflaged in that cedar, and as it left the tree its weight caused the top to spring back in the direction of flight like a catapult. It startled me at first, then filled me with excitement. I know the owls nest on our property because I hear them throughout the year, but it’s rare that I actually get to see one. What followed was an audio extravaganza as the American Crows mobbed the owl some distance away from where I originally flushed it. The recording below captures it all. It’s a bit long- but the cacophony of crows is (hopefully) worth it.
Enjoy.

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Recorded with a Sennheiser ME66 on a Marantz PMD670
00:03 – Owl flushes
00:05 – I swear
00:27 – Crow mob begins
**Tess, my dog, is the one running through the leaves