Yesterday, I postulated that there was a chance for a fallout overnight. An approaching cold front, with scattered showers and thunderstorms, was passing through and would shift the winds from the southwest to the northwest. Such conditions are exactly what is needed for a “fallout,” our “grounding” of nocturnal migrants.

The front came through as expected, and the precipitation was slightly more widespread than predicted. The winds did indeed shift from the southwest to the northwest by morning. Now, I could have uploaded the radar immediately this morning, but that would have entailed getting up even earlier – or getting out the door even later. Instead, as usual, I elected to go birding first and look at the radar images later.

With the potential for a fallout, I headed down to Portland – since I needed to get some errands done anyway - and began at Evergreen Cemetery. This “urban oasis” is just the spot to enjoy a fallout if said fallout did indeed occur.

Upon arrivals, I was immediately greeted by a small group of Yellow-rumped Warblers and Ruby-crowned Kinglets. A good sign indeed. In the next hour and a half, I estimated 90+ White-throated Sparrows, 60+ Yellow-rumped Warblers, 25+ Ruby-crowned Kinglets, and 12 Chipping Sparrows. 8 Yellow Palm Warblers, 6 Northern Flickers, 5 Hermit Thrushes, 4 Purple Finches, 3 Blue-headed Vireos, 2 Pine Warblers, 2 Savannah Sparrows, 1 Swamp Sparrow, and 1 Dark-eyed Junco rounded out my tally of migrants. Although this was by no means a major fallout, some of these birds – especially the White-throated Sparrows – had definitely arrived overnight, and in a larger concentration than we have been seeing recently. (Meanwhile, over at Hedgehog Mountain Park, Jeannette estimated 75 White-throated Sparrows while walking Sasha. Yesterday, I had 2 white-throats there).

I then birded Capisic Pond Park, which was its usual busy self, but mostly with resident and breeding birds. My migrant count was only 20+ White-throated Sparrows, 9 Yellow-rumped Warblers, and 5 Ruby-crowned Kinglets. Meanwhile, only a few migrants had landed in the “Mercy Woods” area of the Portland Peninsula – although 15+ Savannah Sparrows were present. Unfortunately, I ran out of time – and the wind was really picking up – before I could check out the Eastern Promenade, which has been the site of many a spectacular sparrow fallouts (and I was torn between beginning here or at Evergreen this morning).

So, clearly, some birds were on the move last night. My guess is that some birds were in fact grounded by the weather, but since the clouds cover and then the precipitation arrived earlier than I had expected, there were simply not too many birds in the air last night. Now, to see what actually happened overnight, I turn to our trusty NEXRAD radar.

First, the 10pm image:
Notice the flecks of blue in the area around the radar (based in Gray)? Those are birds on the move. The dark blues, greens, and yellows is precipitation. A very light flight indeed:

And, we confirm that these are in fact birds using the velocity image (see links below):

By midnight, more birds were in the air, as would be expected, but stronger precipitation, including imbedded thunderstorms, are on the way:

By the 2:00am image, we can see that the precipitation is now upon us:

And, by 4:00am, the last line of showers has passed through, and there are very few echoes – birds or anything else – left on the radar in the Greater Portland area:

In other words, the passing cold front did indeed “ground” migrants. However, with so few birds – relatively speaking – in the air early last night, there was simply only so many birds to “fallout.” (Or, at least that’s my interpretation of the events). Regardless, this morning’s birding, coupled with an analysis of the radar images, provides an excellent example of the utility of radar for birding in both bird-finding (if I had check it before I went out) and in putting my observations into context. Now, bring on the “real” fallouts!

By the way, for new readers of my mindless dribble that I call my blog, here’s my Radar Birding 101 entry from last fall to introduce you to the thrills and spills of birding-by-radar.

There’s also an excellent birding-by-radar explanation on the New Jersey Audubon website.

And, I strongly recommend my friend, David’s Woodcreeper.com for full analysis of the night’s flight over New Jersey. Although that is of only indirect relevance to us, his thorough, educated, and insightful discussion of each night’s movement - or lackthereof - is quite helpful in teaching us how to interpret the images from here in Maine, or anywhere else. I also recommend taking a look at the regional mosaic that he posts to get a broad view of what is happening each night – I check it every day before I “zoom in” and look at our local radar image.

In other news, there’s a new and improved Maine Environmental News website up and running.

And, finally today, I wanted to call your attention to a significant environmental and birding issue that is going on down in South Texas. Here’s an email that I recently received from David Sibley that I think – especially including his blog entry on the topic – sums it up nicely:

“Hi all,

"Please excuse this group email and the political message, but I'm sending this because I think it the Border Wall is such an important issue. You're probably already aware of it (if not, you can start at my blog here www.sibleyguides.blogspot.com). And if you're already getting involved - thank you.

“I feel very strongly that this is an issue that birders should rally around, since the planned wall is so clearly bad for birds and for birding. Imagine having to go through a checkpoint to get to the Sabal Palm Grove, or having a bulldozed swath over 50 yards wide through parts of the LRGV National Wildlife Refuge. An outcry from birders is one of the best ways to make members of Congress take notice and get involved to alter the plans that they put in place a couple of years ago.

“George Jakobi and The Good Tern Foundation in Texas want to do just that (see http://www.thegoodternfoundation.org/project-borderfence.html), and some of you have probably just received an email from them. Please check out their message and do what you can to raise awareness and defend the birds and birding sites of the border.

“Thanks and Best wishes,
David Sibley”