Friday, June 22, 2018

It's Purple Martin roost season!


The annual gathering of Purple Martins beneath the Causeway is underway!  I visited the roost at the Metairie shoreline this evening, and could detect a couple thousand birds.  Keep in mind that, when I studied the roost extensively three years ago, counts of the departing birds in the morning (a steady directional flow that can be quantified easily) were consistently much higher than could be obtained in evening (when they form swirling masses). As usual, they were clinging to the edges of the lengthwise concrete beams underneath the bridge, both on its west and east faces and underneath.    My poor and grainy video shows the scene on the west face.



The appeal of the Metairie roost is that some of the birds are quite close, and can be easily viewed while perched.  As I have noticed before, the birds appear to be essentially all females and immatures- which have pale gray on the underparts and much of the head.  Out of a couple hundred examined closely, none were adult males (which would appear all black in dusk lighting).

The roost at the Mandeville end of the Causeway is usually much larger, but is too far from shore to be seen from land.  Three years ago when I kayaked out at night (not advisable- lots of speed boats!) I was able to reach 125,000 of them and estimated that the total number may have been twice that, based on the extent of the whitewash seen there from a boat during the day..

That roost off Mandeville is active again this year, as judged from the green blob in last night's radar image (thank you, rap.ucar.edu):


 Good birding!

Peter

Sunday, April 29, 2018

Evening departure


I just pulled up the radar (a site that does not filter out birds:  rap.ucar.edu) and looked at the latest radar images.  A mass of intense reflections appears to be lifting from coastal or near coastal areas and progressing northward.  Birds that crossed the Gulf today and were forced to stop in the wetlands and barrier islands at and near the coast by the north-ish winds that occurred around mid day.  Or so I would guess.

For verification, I stepped outside just now (9:20)  and watched the moon with binoculars for 5 minutes.  Six bird silhouettes (songbird-like) crossed it northbound, most quite high up, presumably migrants departing from points south.  Another that looked more like it might have been a shorebird crossed westward, a path harder to interpret.  Six in 5 minutes is a pretty good rate, compared to most most moon-watching I have done.  Because the coastal birds will be beyond us soon on tonight's northward movement, I wouldn't expect many to visible as silhouettes against the moon for long.

Last night there seems to have been another departure, as evidenced by radar images and by a Wood Thrush that I found around 10 pm stunned on the sidewalk in front of a hotel in Harvey on the West Bank.  A photo below was taken inside the hotel where I inspected and found no obvious injury.  I have it in a standard "bander's grip."  I blew back the breast feathers and saw that it had a small fat deposit (it appears white) inside the furcular region (the depression between the bird's neck and rib cage), which is typical of migrants.   I put it back outside and presume it fared okay.

Peter


Tuesday, March 20, 2018

The fallacy of small birds being babies


Last week this image appeared on my computer screen, provided as part of the rotating supply of daily imagery that adorns my screensaver.  The software has provided loads of stunning natural scenes, but this one made a faux pas!


This is a quite common misconception about birds, especially among lay people:  that a small bird accompanying a larger bird is  a "baby" of the larger individual.  The caption reads "Eastern Great Egrets," indicating that the two are the same species, and the "Watch carefully young pupil" caption implies the smaller is a youngster.  But they are clearly different species.   The larger is indeed a Great Egret- the same species we have in Louisiana, which is very widespread globally.  The smaller looks to me like an Old World species called the Little Egret, although I have not done the necessary analysis to make a definitive call.  At any rate, it is not a Great Egret!

By the time young birds acquire normal (vs. downy) feathers, they are approximately the same size as adults.  Thus, it basically never makes sense to interpret a small but otherwise normal appearing bird as the baby of a larger bird.  Babies are only smaller than adults when they are still in the downy, stubby-tail phase, which typically only lasts a few weeks out of the nest.

The evening after this picture appeared, my sixteen year old came walking in the front door, excited because he had spied an Eastern Screech Owl on the wire in our front yard.  He promptly announced, "Dad, there's a baby owl on the wire outside!" 

Even in my own family!  Aargh!

Peter

Sunday, February 11, 2018

Urban Barred Owl at 12:30 AM

Yesterday morning at about 20 minutes after midnight, I was on my front step letting my dog answer one last call from nature before retiring for the evening.

Across the street, coming from the midst of a typical residential block, came the hoots of a Barred Owl! The call was atypical:  rather than the usual who cooks for you, who cooks for you-all, it was more like who cooks for you, who cooks.  

Here was a case where familiarity with a bird's tone or general vocal quality was important for making the identification- the hoots were recognizably those of a Barred Owl in clarity, pitch, etc- rather dog-like- even though their cadence was perhaps more like that of a Great Horned.  The latter usually gives a call a few phrases shorter than the classic Barred arrangement, but more deep and breath-y.   

Residential hoods are not typical Barred habitat, but they do wander into such areas sporadically in the winter.  The fact that I am just a few blocks from a pretty woodsy part of the batture probably helps.

I hooted back to it several times (I have been practicing imitating Barred Owls since I was a pre-teen- which is not unusual- it is probably the first owl that most birders learn to copy), and the bird seemed to be trading responses with me.  But it never adopted its standard call.

Sunday, December 17, 2017

What warblers are expected in the New Orleans area in winter?


Yesterday I was driving behind the Walmart in Chalmette, to check out the eagle nest in that vicinity*.   As I drove along the woodland edge, I chanced to notice a mixed songbird flock foraging low in the roadside scrub.  I abruptly halted the car, backed up a bit, and rolled down the passenger side window to "spish" and see what was there.  Yellowrumps charged the car, and with them came a few Orange-crowneds and a drab female Pine.  To my delight and surprise, a Prairie Warbler jointed the group, showing off its bright yellow underparts and neatly-streaked face and side.

The first three species are regular winterers around New Orleans, but Prairie is somewhat atypical.  I generally divide our wintering warbler species into several "tiers" of abundance/likelihood:

TOP TIER
Yellow-rumped Warbler
(Undeniably the most numerous species here in winter; a half day's birding our usual target winter habitats -forest, scrub, and marsh edge- will commonly produce dozens)

SECOND TIER
Orange-crowned Warbler
Pine Warbler
Palm Warbler
Common Yellowthroat
Wilson's Warbler
(All widespread and numerous enough to be found on most such half-day efforts)

THIRD TIER
Black-and-white Warbler
Nashville Warbler
Northern Parula
Yellow Warbler
Yellow-throated Warbler
Black-throated Green Warber
Prairie Warbler
Ovenbird
Northern Waterthrush
(Regularly occurring trophy birds; an active birder might expect to find around half of these in the course of a given winter; if you find one on a Christmas Count, it will probably be a count exclusive)

FOURTH TIER
Everything else that has ever turned up!  This list is long, and ranges from species a relatively small step down from those above (e.g., American Redstart) to some seemingly impossible vagrants (e.g., Lucy's and MacGillivray's Warblers, and Painted Redstart).   

*an adult was sitting low in the nest, evidently incubating.

Tuesday, November 7, 2017

Apparent Tree Swallow roosts in the River Parishes, visible on radar

One highlight of each November is the formation of Tree Swallow mega-roosts in the cane fields of the River Parishes.   A roost in Vaccherie has been estimated at a million birds in years past, but locations change somewhat from year to year.  I have seen them as far downstream as Luling.  They last only until the cane is cut, generally around early December.

The roosts are impressive at dusk, when huge clouds of swallows cover the sky.  Their roost entry is very strange, as the birds do not descend into the cane over a broad area, but instead "drain" from the cloud through a small funnel-shaped pathway they create.  For this reason, this phenomenon is often referred to by local birders as a "swallow tornado."

Cane fields are generally private property, so viewing options may be limited.   Sometimes a nearby river levee provides the best viewing, but sometimes engaging a farmer in conversation can open a door to driving out into the heart of the event and standing next to the funnel.  

The roosts are generally visible on the Slidell radar, when accessed online at a site that does not filter out birds.  The image below is from rap.ucar.edu, taken this morning (the 12:29 UTC on its label indicates 6:30 local time).  There are two obvious donut echos, one of which appears to be between Paincourtville and Belle Rose along (east of) Bayou Lafourche, and the other just east of Laplace, perhaps visible from Hwy 61.  Hidden between them (partially covered by the Belle Rose echo- only the southeast edge of the donut is visible) is  a third one, seemingly near Vaccherie or St. James.


Saturday, September 30, 2017

Roseate Spoonbill among waterbirds at Shrewsbury Flats

Just made a brief swing through the Shrewsbury Flats- the water retention ponds beneath Causeway Boulevard, adjacent to the Earhardt Expressway. 

An immature Roseate Spoonbill was nice, hanging with the 25 or so White Ibis and a scattering of other large waders.

The most surprising bird was a female/immature Hooded Merganser- not a species that was on my radar to turn up here.

The muddy edges are extensive, and shorebird numbers have grown to 80 Least Sandpipers, 35 Black-necked Stilts, and 4 Lesser Yellowlegs.

An adult Common Gallinule was present, which makes it easier to explain the presence of three juveniles that I saw there a few weeks back.  Looks like they nested.

Good birding,

Peter