bird data > past walk reports

10/29/12

Some walks are open fields with salients rising like minarets above the patterned flow of the mundane. The towers allow no subtle parsing. You are almost compelled to fill the opalescent flask of a memory and mix in spices to sprinkle on lesser times. This was the tide of our week. The field contained 21 species, which sounds pretty good. It is pretty good but it is not of special note. We saw more species in four other week 44 walks including the record of 26, set last year. Still, the median is 17 and the low 11, so we are in no position to complain, even by the raw sourcing of a species count. The harbor of special birds was, however, filled with anecdotal joys. We had three first time avian appearances for the season, a second time birder (Agnes), and a pleasant crowd including Ashish, who brought his patented cherub smile although he seemed almost naked without his camera. It was a nice walk.

See the plots at http://birdwalks.caltech.edu/bird_data/species_time.html and http://birdwalks.caltech.edu/bird_data/two_plots.htm

I will play favorites in describing highlights. The Say's phoebe in the playing field deserves a note. We seem to have missed the initial week 40-41 pulse of Say's phoebes passing through town and we are now seeing some of the migratory laggards. These birds typically stay around the playing field for a few days with visits often extending up to a week or two. Occasionally, perhaps four or five times since our first Say's appeared in 1999, a bird will decide to stay for a month or more and we get a lot of successive sightings. Unfortunately, this does not usually happen with the first bird of the season, so I am not overly hopeful that next week will yield another Say's.

A Say's phoebe is always welcome but the most spectacular bird of the day was also the last bird of the day. We were walking up the path winding around the Throop ponds, hoping for a wren, when Viveca instead notices a dove/pigeon sized bird engaging in some desultory pecking along a branch overhanging mallard pond. This seemed very odd behavior for a mourning dove but the dove soon morphed into a female northern flicker. She is not nearly as flashy looking as a male but there is still a lot to see in this bird and she offered a fairly patient pose before flying off without finding a suitable meal.

Northern flickers are winter birds for us. We have a few sightings from August but 90 per cent of our sightings are encompassed between weeks 42 (late October) and week 12 (late March). It's also fair to say that the sightings data are distorted by some unusually flicker rich years. We've had 58 northern flicker sightings on the Caltech bird walk, which might make you think that they are not super rare, but more than thirty of those sightings came between 1988 and 1993. In the last decade, we have claimed only 13 flickers, making it a once or so every year type of bird but, even here, the counts are misleading. We had pulses of three and four sightings in 2009 and 2011 but none in the years 2005-2007 or 2010. Since flickers tend to be somewhat talkative and the birds are neither small nor shy, I think it fair to say that we catch a lot of the available flickers and that there just aren't a lot of these birds on campus.

I have yet to speak of our bird of the week. It comes in a smaller, less flamboyant package than the flicker but it is no less welcome. As the group approaches Wilson, Viveca wanders into the Morrisroe garden. Vicky and I, lagging behind, arrive at the corner of the fencing looking into the garden just in time to see the curious head of a dark-eyed junco. Viveca, who was by now on the inside looking outward, got a much better view. We had a dark-eyed junco. Dark-eyed juncos have been active up in the foothills for some time but this is the first junco of the season for the Caltech bird walk.

Dark-eyed juncos are strictly winter season birds for us. Every sighting but one lies in the range defined by week 42 (late October) in the Fall and week 13 (late March) in the Spring (in 2010, we had one anomalously late sighting in week 17). The bulk of the sightings come from week 49 through 12 (i.e., early December through late April). From a year-to-year perspective, dark-eyed junco sightings on the Caltech bird walk are episodic. The sightings have come in three pulses, 1986-1991 (16 sightings), 1996-1998 (3 sightings), and 2004 - present (37 and counting), so that the general pattern seems to be one of sightings for some number of successive years followed by four or five years of juncoless walks. If we were doing walks up in the foothills, there would be variations in the number of sightings but juncos would be sighted every year. So, it seems likely that one factor encouraging a junco to think about Caltech is a stress in habitat further upslope. A second important consideration is the quality of sparrow habitat on campus. If we had a bad year for house sparrows, which I take to be an indicator of sparrow habitat quality, we had a bad year for juncos. Taking apart a recent spurt in junco sightings that is likely driven by the Station fire, less than 40 house sparrow sightings in a year meant no juncos. I admit to our seeing one dark eyed junco in 1998 when there were only 38 house sparrow sightings but, to me, that is no more than an exception to emphasize a rule.

During the breeding season, dark-eyed juncos are socially monogamous birds leavened in a thick frosting of lothario. They were classically thought to be monogamous, both socially and in reality but DNA testing shows that 20 or 30 per cent of female juncos engage in affairs leading to progeny. The females socially mated to males that have affairs (aka the lotharios) almost never have affairs of their own and the males whose mates have affairs almost never engage in affairs themselves or, perhaps I should say, they are rarely successful in any affairs they might attempt to engage in. This is a curious dichotomy. One would think that a lothario off hunting for potential affairs would be susceptible to having his mate engage in them behind his absence. However, it doesn't seem to work that way in the junco world. A lothario will sneak into a nearby territory near dusk, dash in for a quick frolic, and dash back to his home territory. This may be timed perfectly so that a rival is unable to claim a similar visitation with his mate. However, a lothario's breeding success may be a reflection of extraordinary fitness, so his mate, even given the opportunity to breed with a less fit male, will choose not to. Nevertheless, there may well be a hidden cost for our lothario. The time he spends trying to set up liaisons with the neighbors is time not spent caring for the progeny of his social mate. This can lead to lower fledging rates so that his overall reproductive success may not be much better than if he had just stayed home.

The date: 10/29/2012
The week number: 44
The walk number: 1167
The weather: 82 F, sunny

The walkers: Alan Cummings, John Beckett, Kent Potter, Viveca Sapin-Areeda, Ashish Maharbal, Vicky Brennan, Agnes Tong

The birds (21):

Mourning Dove
House Finch
Anna's Hummingbird
Acorn Woodpecker
American Crow
Lesser Goldfinch
Black Phoebe
Mallard
European Starling
Yellow-rumped Warbler
Western Meadowlark
Say's Phoebe
Bushtit
Ruby-crowned Kinglet
Dark-eyed Junco
California Towhee
Townsend's Warbler
Common Raven
White-throated Swift
Hummingbird, Selasphorus
Northern Flicker

--- John Beckett

Respectfully submitted,
Alan Cummings
11/21/12

http://birdwalks.caltech.edu/index.html





10/22/12

This was not a spectacular walk with rare birds dripping from every branch. Nor did we see any extraordinarily rare birds. We were, however, dripping in time as a wave of season swept through and around us. We were dripping in the season. By the numbers, our total of 20 species was just three below the record of 23 set in week 43 of 2005 and well above the median (16) and minimum (10).

See the plots at http://birdwalks.caltech.edu/bird_data/species_time.html and http://birdwalks.caltech.edu/bird_data/two_plots.htm

There were all sorts of highlights. We didn't see any rare birds but we did have the season's first sighting of a ruby-crowned kinglet, the season's first sighting of a cedar waxwing, the season's first sighting of an American goldfinch, and the season's first sighting of a rufous hummingbird. Were it not for a single confused juvenile rooting through the bushes outside Braun last week, it would also have been the season's first sighting of a white-crowned sparrow. These birds are a binding tessellation. They outline our seasons and guard the boundaries of cold and rain. Left to our own devices, we might wait until a cold snap or Thanksgiving to declare the Fall but the birds know better and the cacophony of their arrival is the mark of the season. The Fall is here.

Perhaps, the most revelatory sighting of our walk was a ruby crowned kinglet in the Maintenance yard. It was rooting through the fence bushes on the north side, moving fast and gleaning faster. Generally speaking, kinglets are in a hurry to live. Do the math. If the total population is stable, and you are in one of 12 eggs, the odds of your surviving to your first birthday are not in your favor. Kinglets carry a heavy mortality load through life but they seem determined to make the most of it.

During the breeding season, kinglets look for mature high canopy spruce and ponderosa pine and relatively dense cover. This means that logging and fires are bad news for kinglets and riparian buffer zones need to be really wide to be useful, much wider than loggers are willing to contemplate. In the winter, kinglets are much more cosmopolitan. They are partial to our oaks but you can find a kinglet in almost anything. If you have roses, kinglets are your friends. Forget the soapy water. I've seen a kinglet vacuum his way right up an aphid encrusted branch, drop a few centimeters, move 30 or 40 degrees and vacuum again, repeating several times. Forget the dormant oil. My aphid problem disappeared in a week's beak and no toxicity.

Ruby crowned kinglets are a reliable marker of the Fall, generally arriving a week or two after yellow-rumped warblers (they leave the breeding grounds a week or two after the local warblers) but this is a sliding target. In the early 90s, we were seeing them as early as week 39 and, between 1989 and 1997, the average was week 40. Since then, we have generally been picking them up a little later in the year (the average is week 42), although the distribution is more scattered. So, a first sighting of the season at week 43 is consistent with the modern paradigm. I'm not sure what the modern paradigm represents but, given that kinglets are pretty easy to pick up when they are around, this seems to be a real effect. There are more Caltech birders on average now than there were in the 90s and kinglets are not hard to find when they are around. Yet, we are seeing kinglets coming in later. One possibility is that the kinglets who like to winter on campus are in fact coming in later but this doesn't explain the scatter. Our last Spring sighting has held fairly steady, around week 13, only once (1997) extending beyond week 15. So, I'm inclined to think that our principal winter residents have been arriving around weeks 42 or 43 all along. Another possibility is that we are not always seeing juveniles, who generally start south a week or two before the adults. Had big deficits of juveniles been occurring throughout the last decade, there wouldn't be any kinglets at all by now. However, we could be seeing some stress on the general population, even though kinglets in the west are supposedly stable or even experiencing a mild population increase. If you have a good year, you have lots of juveniles wandering through campus around week 40 or 41 and we see them. If it's a bad year, we may miss them. By this theory, the 90s were very good for kinglets with lots of juveniles and the last decade has been much less successful. Unfortunately, juvenile ruby crowned kinglets look like adult male kinglets who look like adult female kinglets unless you happen to catch one in an excited state. So, we can't establish variations in sex or juvenile versus adult ratios by arrival time or residence (the situation is also complicated because kinglets segregate by sex in their wintering ranges - males tend to get the good territories and winter further north on average).

Now, since I don't actually know what the reason behind the scatter in first Fall kinglet sightings is and I don't have much data to work with, I will paper mache another possible natural history for you. Perhaps, we have two populations of Fall kinglets, one composed of wintering residents that stay on campus and another that passes by a week or two earlier. This latter population experienced a significant decline in the late 90s. This is not a sign of the extirpation of breeding kinglets in the San Gabriel Mountains. They were gone by the 1980s. Nor would we see evidence for this population in the Spring statistics. A migrating kinglet passing through campus on his way back north, a week or two before our kinglets leave, would be confused with a winter resident. We still have early sightings in the Fall (it was week 40 in 2010), so these putative rare birds are still with us, which is one reason, I think we may be seeing a muted reflection of the year's breeding success (i.e., we are catching or not catching juveniles). The increased scatter in first Fall sightings in recent years reflects whether or not we manage to catch the through traffic heading south and, I would assert, whether these are adults from some region of Canada heading to Mexico or juveniles from the same breeding areas as our wintering adults, that there are often fewer of them to see.

The date: 10/22/2012
The week number: 43
The walk number: 1166
The weather: 67 F, partly cloudy

The walkers: Alan Cummings, John Beckett, Melanie Channon, Vicky Brennan, Viveca Sapin-Areeda

The birds (20):

Scrub Jay
Northern Mockingbird
Mourning Dove
House Finch
Anna's Hummingbird
American Crow
Red-tailed Hawk
Common Raven
Yellow-rumped Warbler
White-throated Swift
Lesser Goldfinch
Ruby-crowned Kinglet
White-crowned Sparrow
Wren, species
American Goldfinch
Band-tailed Pigeon
Orange-crowned Warbler
Black Phoebe
Cedar Waxwing
Hummingbird, Rufous

--- John Beckett

Respectfully submitted,
Alan Cummings
11/19/12

http://birdwalks.caltech.edu/index.html





10/15/12

For me to hold a day to yesterday, I have to grasp a sere cloud in a blue sky and look for rain. I have to see an afterglow in a passing thought and conjure mysteries. I have to be within a spatial pattern's gloss. I see the petals of birds in the ashes untied to the images and sounds of any particular week, although I do have a sense of season and what was seen and where over the last few weeks. This time, we have another 20 species walk with a passing resemblance to last week. We saw one meadowlark, not four but that still counts for a two successive weeks of meadowlarks. Barbara brought along a friend, Karen Scauzillo, who is our 133rd new walker. I don't know when the last time we had new walkers come in successive weeks but it must be rare, at the least, a once every few years type of event. Yellow rumped warblers were not rare but our corvids decided to be scarce. We didn't hear a single crow and failed to see a raven but we did pick up a solitary white-crowned sparrow, the first of the season and, for the first time in a couple of years, a red-naped sapsucker. Our snowy egret sighting counts as the most anomalous snowy ever for reasons I describe below.

The final tally of 20 species is comfortably above the median (16) and minimum (9). We were well below the record of 29 observed in 2010 but our species total was the fourth most in week 42, after 2009 (21), 2011 (25), and 2010 (29). This is another way of saying that the top four week 42 species counts for the Caltech bird walk are from the four most recent week 42s. It kind of reminds me of global warming.

See the plots at http://birdwalks.caltech.edu/bird_data/species_time.html and http://birdwalks.caltech.edu/bird_data/two_plots.htm

Our most unusual sighting has to be the snowy egret. We have had 29 snowy egret sightings on the Caltech bird walk over the years but these are all bunched in the winter/Spring, weeks 50 through week 16, and episodic, occurring in only seven different years, although three of those are the current and previous two years. A week 42 snowy egret sighting is by far the earliest we have; we shouldn't be seeing one of these birds for another couple of months, if then. We will, however, take what we can get. If we see this bird next week, we will be tied with 2002 for the most snowy egret sightings in a calendar year with nine. It's a pity that we can't band these birds. It would have been interesting to know whether we are seeing one individual using Caltech as one of his collection of fishing holes over the last couple of years or multiple individuals that happen to stop by at odd times in the winter and Spring.

As interesting and unusual as the snowy egret was, the bird of the week has to be the red-naped sapsucker who, as Viveca and I were walking along Holliston Ave., flew directly over our heads and landed in a tree about 15 meters in front of us. He chose a well exposed perch and stayed there for several minutes, long enough for Alan to loop back and get a good look of his own. This was our fifteenth sighting of a red-naped sapsucker. With the exception of one seriously confused bird from July of 2009, presumably a juvenile, all of these sightings come between weeks 41 and week 13 with pulses in weeks 41-44 and 5-8. Our two sightings of a red-naped x red-breasted hybrid also came within one of these pulse periods (weeks 41 and 43). Sightings of red-breasted sapsuckers (14 total) appear to be more wintery, coming mostly in weeks 47 through 13. We are on the extreme western edge of the red-naped sapsucker's wintering territory, so observations are possible anytime in the Fall, after week 40, through the Spring but most of our birds are probably in the process of migrating to Mexico for winter or to the Rockies or Sierras for the breeding season, although there are some isolated breeding populations in southern California mountains.

Before mitochondrial DNA came on to the scene, the sapsucker speciation world could only be described as confused. Everybody thought that Williamson sapsuckers were something different but after that, trouble came in bunches. Were sapsuckers one superspecies composed of yellow-bellied sapsuckers, red-naped sapsuckers and red-breasted sapsuckers or three separate species? There were clear but restricted hybridization regions, which suggested separate species, but there were also troubling aspects. Female red-naped sapsuckers have an unquestionable "lust for red" and hybridize with male red-breasted sapsuckers, whenever the opportunity arises, which happens not infrequently in Oregon, northern California and parts of Nevada. These unions fledge just as many juveniles as their peers. The back crosses don't do so well but this appears to be more about prejudice than fertility. For decades, the issue of speciation moved like a tide built on the force of personality but, generally, the sapsuckers were relegated to a yellow-bellied red-naped complex.

So, what does the DNA say? It says that Williamson sapsuckers are quite different from yellow-bellied, red-naped, and red-breasted sapsuckers. Those old ornithologists were no fools. Yellow-bellied, red-naped, and red-breasted sapsuckers are very closely related. Red-naped, and red-breasted sapsuckers are so close that they represented the most closely related birds still regarded as separate species with a mitochondrial drift suggesting separation of the populations occurred less than a million years ago. However, even with the DNA studies, separation into three distinct species, which was officially accepted in the 1980s by the American Ornithological Union, was couched in a lot of "on balance" arguments.

In discussing sapsuckers, the first point of reference, even if it isn't the most obvious, is that they are vitally important primary hole nesters. They generally want a tree with heart wood rot (aspens are particularly prone to this) and they generally drill holes in the same tree over multiple years, starting relatively low, as low as a couple of meters, and working their way up (you can think of heart wood rot as a tapered cone inside the tree; the sapsucker is looking for a particular combination of strong outer wood with easily excavated rotten inner wood). Both sexes exhibit strong site fidelity and, therefore, a fairly strong mate fidelity. Red-naped sapsuckers are willing to work with snags (standing dead trees) but, unlike flickers, they don't go out of their way to find them. Since a sapsucker makes a new nesting hole every year, he is providing nesting sites for a wide variety of weak primary hole nesters like chickadees and a host of secondary hole nesters like tree and violet-green swallows, bluebirds, robins, warblers and wrens that can't make or modify their own holes. There probably isn't a more desirable commodity in the life of a secondary hole nester than a prime sapsucker nesting hole.

A second and more obvious point of reference is that sapsuckers drill for sap. If you go to the eastern side of Tournament Park and look at trees on the other side of the property line, you will find one with prominent horizontal sets of holes snaking up the tree. These are sap wells drilled out by a sapsucker several years ago. I don't know about this bird but usually a sapsucker will start drilling sap wells low on the tree or a branch and work his way up. Occasionally, they will tear off strips of bark instead of drilling wells but the effect is the same. The tree weeps and the sapsucker sips and opportunistically eats insects that have been attracted to the sap. They feed the sapsucker making them but they also feed several dozen other species, including butterflies, wasps, hummingbirds, warblers, squirrels, and chipmunks. The sapsucker will defend his sap wells but it's not too hard to work your way around his schedule. Sap wells are a supermarket.

The date: 10/15/2012
The week number: 42
The walk number: 1165
The weather: 91 F, sunny

The walkers: Alan Cummings, Barbara Ellis, Karen Scauzillo, Kent Potter, John Beckett, Vicky Brennan, Viveca Sapin-Areeda

The birds (20):

Scrub Jay
Northern Mockingbird
Mourning Dove
House Finch
Anna's Hummingbird
Acorn Woodpecker
Mallard
Red-tailed Hawk
Lesser Goldfinch
Yellow-rumped Warbler
Western Meadowlark
Black Phoebe
Turkey Vulture
Spotted Towhee
Yellow-chevroned Parakeet
House Wren
White-throated Swift
White-crowned Sparrow
Red-naped Sapsucker
Snowy Egret

--- John Beckett

Respectfully submitted,
Alan Cummings
10/22/12

http://birdwalks.caltech.edu/index.html





10/8/12

We are back! We are back! We are back in the twenties after four months spent toiling in the teens (or worse in one case). There are now birds to be had and birds to be seen, as if the westerlies had suddenly swelled into our hearts after months without a single fluttering sail calling to the wind. It is the swell of marking passages and new homes. The Fall migration has arrived and the species count reflects it. We ended up with 20 species on the nose, well above the low of 12 and median of 16 and we also picked up some meadowlarks along the way. The record for total number of species in a week 41 walk is 24, set in 2010 and matched last year but who cares. The twenties are back!

See the plots at http://birdwalks.caltech.edu/bird_data/species_time.html and http://birdwalks.caltech.edu/bird_data/two_plots.htm

Next week the record is a rather formidable 29. Ruby-crowned kinglets, white-crowned sparrows, and hermit thrushes are plausible targets. We have yet to see any black-throated gray or Townsend warblers this season. Orange-crowned warblers are around but, as yet, in low abundance. That may change. Yellow-rumped warblers are around and in high abundance, so high that a lot of time is spent sifting through yellow rumps to see if something different is among them. That will hopefully stay the same.

We had two highlights for the day. The first was a new walker, Agnes Tong. Agnes is our 132nd walker and the second of this year, Richard Price being the other. On the avian front, the highlight bird of the day has to be a grounded cluster of western meadowlarks in a rough patch of grass in the outfield of the baseball field. Meadowlarks are a sporadic, once a year sort of capture for us, invariably in the grass of the baseball field or track but we definitely have a shot at more of them for the next month.

I offer a meadowlark conundrum for your consideration and a couple of idle speculations. I have no solution, although I expect that somebody else in the group does. Week 41 is easily our most common sightings week for this species (9 of 27 sightings have come from week 41). So, our sighting this week is typical of our record for intersecting this species. So, where is the conundrum? It's too typical. Twenty five of our 27 sightings are from weeks 39 - 45. Where do these birds come from and where are they going? They generally don't stick around Caltech for long, so we are just a brief way station. Nor, at first sight, does this seem to be a migration thing. It is true that meadowlarks at high elevations move down and birds breeding in the far north move south for the winter. However, we have a Caltech pattern of one big blast in October - November with no corresponding pulse in the Spring. I also don't see this as juvenile dispersal pattern as that would likely show up a month earlier than we see it and meadowlarks usually double clutch, so we should be seeing multiple juvenile pulses if that what was going on and we don't.

Just to get your idle speculation juices flowing, I'll give you some possibilities to eschew if you want to. One is that our birds move in small flocks in the Fall and large flocks in the Spring [we are more likely to get a bird walk sighting if thirty birds pass by in ten three bird flocks (e.g., Fall) than if they go by in one thirty bird flock (e.g., Spring)]. Meadowlarks are known to form large winter flocks. Another possibility is that these birds are leaving some agricultural regime that closes off in October (alfalfa?). Perhaps the pattern of movement is somewhat analagous to that of red-masked parakeets, always in the general area, more or less, and hence resident. However, they follow the food from place to place and you end up with a seasonal distribution of the birds if you stay sessile or walk the same birding route every week.

OK, it's your turn. Meadowlarks eat insects when they can, which is basically Spring into summer, but will eat corn or oats if none are available and this actually got them into trouble at the beginning of the twentieth century when farmers in California were trying to get meadowlarks declared agricultural pests so that they could slaughter them and get the government to slaughter the birds for them (the Mao approach to horticulture). However, when they funded a study to prove how bad these birds were for crops, the guy who did the study discovered that meadowlarks ate a lot more grasshoppers than seeds, ate more weed seeds than crop seeds, and that they resorted to vegetable matter (thereby putting on a seed eating and sprout destroying show for Mr. Farmer) mostly when they couldn't find an insect. On balance, they were a beneficial for crops. The farmers put their shotguns away.

For the factoid of the week, I suppose I should go with the obvious. Meadowlarks are not larks. They are actually in the same family (icterids) as orioles and blackbirds.

I was thinking about those overheated black birds of last week. One of the downsides of being black is that you are going to get hotter in hot weather than you would if you stuck to a lighter color, especially if you are out in the sunlight. We are in a sun drenched arid regime. It's hot out there. You don't need to take in extra heat to keep warm. Maybe a soaring bird like a raven or a turkey vulture needs the black (actually dark brown for the vulture) for loft but a crow doesn't do a lot of soaring. So, why bother? What's the point of being all black or having black feathers or being like an indigo bunting, where black feathers turn to blue in your view because of light refraction effects?

As is usual, the answer is many answers and ours begin with eumelanin, a polymer that is also a pigment. I mentioned heat absorption. Another reason you might want to have some eumelanin around is that you can develop part of your color palette from it. Depending on concentration, you can get various shades of dull grays to black. If you put your eumelanin granules into ordered arrays, you can develop iridescence. A third important reason for investing in eumelanins is that you can cluster your eumalanins in melanasomes and strengthen a feather. This is likely why birds that are mostly white, like white pelicans or many gulls, often have wing tips or edgings of black where feathers take the most stress. Sounds good but I'm not done. Eumelanis, or the dark brown phaeomelanins, are natural anti-oxidants because they can suck up free radicals and also bind heavy metals. They are your first line of defense against heavy metal poisoning. Not enough? Eumelanins are antibacterial and antifungal. You are likely to be a healthier bird if you use eumelanins. They also transform UV radiation into heat optimized to absorb around 340 nm (UV). The more melanin you as a human have, the less likely you are to develop UV related diseases like skin cancer. Of course, every blessing is a curse. The more melanin you have, the more likely a vitamin D deficiency is.

I mentioned that eumelanins can act as traps for copper and heavy metals. This fact actually gets used in the paleontological study of fossil feathers to discern where eumelanins were located in the past. For example, based on copper concentrations in fossil feathers, you can tell that Confuciusornis sanctus, the earliest known member of Ornithurae (lower Cretaceous, about 120-130 Myr), definitely had variably distributed eumelanins and was probably a darkish "bird". In case you are wondering, Archaeopteryx, is older (circa 150 Myr) but more dinosaur than bird; Confuciusornis is much more bird than dinosaur - it has a true avian beak and, most importantly from a classification perspective, a short tail (not to be confused with tail feathers, which were actually quite long in this species). So, eumelanins were clearly viewed as a winner by "birds" of the Cretaceous. They are still winners today.

The date: 10/08/2012
The week number: 41
The walk number: 1164
The weather: 73 F, partly cloudy

The walkers: Alan Cummings, Kent Potter, Viveca Sapin-Areeda, Carole Worra, John Beckett, Vicky Brennan, Agnes Tong, Tom Palfrey

The birds (20):

Scrub Jay
Northern Mockingbird
House Finch
Anna's Hummingbird
American Crow
Mallard
Turkey Vulture
Western Meadowlark
Lesser Goldfinch
Red-tailed Hawk
House Wren
Common Raven
Yellow-rumped Warbler
Warbler, species
Hummingbird, Selasphorus
Bushtit
Black Phoebe
Band-tailed Pigeon
Yellow-chevroned Parakeet
Cooper's Hawk

--- John Beckett

Respectfully submitted,
Alan Cummings
10/15/12

http://birdwalks.caltech.edu/index.html





10/1/12

There are signs of heat stress everywhere in this walk. Even before the beginning, I wander over to the Throop ponds to check for a duck before proceeding to the starting point of the walk, as I do each week. I am absent luck today. There is no mallard for me, although it is worth noting that a drake appeared to be settling in later in the week. He is newly molted post breeding (you can tell because the breast is a solid bright brown; if he has been fighting for females and/or social position, you will see gouges where a rival has snipped out a few feathers). Next week may bring an official duck but, this week, I see only a squirrel plastered over a branch. He seems totally engrossed in finding cool thoughts but they are elusive. He is so close that I could touch him were I to lift a hand. He has a sifting head and casts a baleful eye towards me as he realizes that I am watching him. "Do I have to get up and move higher? I surely don't want to but he might be dangerous. Does he have nuts for me? He might mean food." The slowly churning cogitation never blooms into an action as I turn away and migrate down to the starting point for the walk. We begin with no birds.

A walk is like a little benediction. At the beginning, we gather in a little cluster. Some of us bring an offering to the list, the odd bird seen on the way to the walk. Others bring stories, just as important but not listable. There are chickadees, lots of chickadees, in Sierra Madre. The San Gabriel Mountains are full of warblers. There were four western bluebirds in my bird bath this morning. You never know. This time, the stories are weak as we find ourselves considering what is likely to be a hot walk. Alan already has his collar up to protect the back of his neck. By the time we get to the back parking lot at the Health Center, which is normally our first stop, Alan is already hopping from shade to shade. There are two crows in Tournament Park, mouths gaping into the hot air. As we cross Michigan Avenue near the ticket office, Alan notices that the sprinklers are running. He walks right into the middle of the spray, lifting his binoculars above his head and, like an overheated supplicant, he is soon soaked to the waist. In the meantime, Viveca and I check out an acorn woodpecker in the shade side of a palm tree and, fittingly her beak is open to the sky. This is the down side of owning black feathers. It's very hot, even in the shade. Alan, who had dismissed the acorn woodpecker with a glance, joins us on the sidewalk, only partly satisfied with his swamp cooler exercise. He eventually admits that he should have dropped to his knees and allowed a torso soak. Viveca and I elect not to get wet but I agree with the birds. It is hot. "How hot?" you ask. I tend to judge how strenuous a walk is by how much water I consume immediately after the walk. For me, it was a one liter day, which is at the upper end of my scale.

Ah yes. I suppose I should mention the results. We did fairly well considering the conditions but we tied for the second lowest week 40 species total of all time (the low was an 8 bird walk set in 2008). We were well below the median of 16 and the record high of 25 was but a distant dream. Except for a handful of yellow-rumped warblers who were actively foraging in Tournament Park, probably because they had just landed after a long migration and were seriously hungry, the birds were generally sessile and stressed. For myself, I would have to say that the yellow rumped warblers were the birds of the day. They may have come in with a whimpering in week 39 but, in week 40, the yellow rumped warblers are now here in force. The Fall is really here. I can feel it through the heat and I know it like the abyss of a cleansing mind. The heat is nothing but an aberration swept away in every gleaning warbler leap. The Fall is here.

See the plots at http://birdwalks.caltech.edu/bird_data/species_time.html and http://birdwalks.caltech.edu/bird_data/two_plots.htm

I got a stellar view of a Cooper's hawk complete with a stark white rump patch, which you don't usually see in a flat area like campus because you tend not to get a good angle for it. She was flying across the parking lot of the child care center. On the merits, however, the bird of the day belongs to Alan's robin, which he saw in the back yard of Morrisroe. The migratory robins are coming through, leading to a rising pulse of sightings starting in week 40 and cresting in week 43. Some of these birds will decide to winter around campus and this will yield sightings from now until week 20 or so of next year. We should also be seeing ruby crowned kinglets as they generally arrive within a week of the yellow rumps and white crowned sparrows are readily acquired in the foothills around town already although they have been a scattered capture for us on campus over the last few years. Wilson's and yellow warblers will, however, be high profile targets for the next two or three weeks. You have to catch them fast as they will not be sticking around. I hope for cool. After today's walk, I am ready for cool. I am ready for the Fall. I am beyond ready.

I forgot to mention my favorite white breasted nuthatch factoid last week and, given that it might be another decade or a week before we see another one, I thought I would just blurt it out now, rather than talk about robins. It is a matter of beetle juice and not a matter of Burton. Nuthatches will rub beetle juice all around the area of their nesting holes, both outside and inside the hole but especially outside. Sometimes, they accomplish this by taking a beetle and rubbing with it until there is nothing left. Sometimes, they slice open the beetle and then dip a beak into the vessel to put a layer of beetle juice on the beak and then rub a wetted beak onto the bark. This is most common in areas where squirrels compete for nesting/roosting holes or have a standard path up the nuthatches chosen nesting tree. It must act as a squirrel deterrent at some level, perhaps depending on the species of beetle and how sensitive little squirrely feet and nostrils are to it, and I have to admit that I'm tempted to try it at home, where several squirrels are resident, just to see what a squirrel does when confronted by a tree smeared in beetle juice. This sounds like a project for a ten year old. I'm ready.

The date: 10/01/2012
The week number: 40
The walk number: 1163
The weather: 103 F, sunny

The walkers: Alan Cummings, John Beckett, Viveca Sapin-Areeda

The birds (11):

Rock Dove
House Finch
Anna's Hummingbird
Acorn Woodpecker
American Crow
Lesser Goldfinch
Black Phoebe
Yellow rumped Warbler
Hummingbird, Selasphorus
American Robin
Cooper's Hawk

--- John Beckett

Respectfully submitted,
Alan Cummings
10/9/12

http://birdwalks.caltech.edu/index.html





current walk report / two time plots / probability plots / raw data