Tuesday, April 26, 2016

International Migratory Bird Day + “The Messenger”


International Migratory Bird Day is celebrated here every year on the second Saturday in May and this year there are some great activities to help you celebrate on May 14th!



Join us at Oak Hammock Marsh on May 14th for any of the following:

* 8 - 10 a.m.:       Birding Marshwalk with Christian Artuso and Tim Poole - Birds recorded on the walk will be entered in eBird

* 10 - 11 a.m:      IBA Program and Data Entry – Learn how to record birds in eBird with Tim Poole and Christian Artuso

* 11 a.m. - noon: Manitoba’s Returning Songbirds presentation by Christian Artuso

* 1 - 2 p.m.:         Birding by Ear Workshop with Paula Grieef - Learn some basics for identifying bird songs in this beginner workshop.  $5 plus admission

* 2:30 - 3:30 p.m.:  Buying Binoculars presentation - What to look for when buying binoculars with Paula Grieef and Ricky Ryan from Zeiss. Binoculars will be available for testing. Enter to win a pair of Zeiss binoculars.

During the week of International Migratory Bird Day, the superb documentary “The Messenger”, which chronicles the struggles of songbirds in the face of habitat destruction, climate change and industrialization, will be featured at Winnipeg’s Bandwidth Theatre on May 13 – 19, playing at 7 p.m. daily with 5 p.m. matinées on Saturday and Sunday. On the “auspicious” Friday May 13 I will be there to introduce the screening.

I will also be leading a birding workshop at St Leon on April 30th for any of you in that neck of the woods who might be interested. On the evening of May 12th I will be doing a condensed Birding By Ear Workshop at FortWhyte Alive.

Good birding all; May is just around the corner and such a wondrous time in Manitoba!

Here are two photos of a male Baltimore Oriole I photographed recently in Costa Rica — one of many birds getting ready for the northward trek to brighten our lives up here in the temperate zones!
 

Tuesday, April 5, 2016

Comparison of Campephilus and Dryocopus:

The four photos used in this collage are:
Top left: Pale-billed Woodpecker (Campephilus guatemalensis), female, Bahía Drake, Costa Rica.
Top right: Pale-billed Woodpecker (Campephilus guatemalensis), female, Playa de Oro, Colima, Mexico.
Bottom left: Lineated Woodpecker (Dryocopus lineatus), male, Río Lagartos, Yucatán, Mexico.
Bottom right: Lineated Woodpecker (Dryocopus lineatus), male, Chaparri, Lambayeque, Peru.



I have posted previously about the differences in toe structure and perching posture of woodpeckers (see: http://artusobirds.blogspot.ca/2015/01/why-woodpecker-lost-toe.html); however a recent photo opportunity in Costa Rica reminded me that I now have a chance to comment further on the postural differences between two of the largest woodpecker genera: Campephilus and Dryocopus.

Pale-billed Woodpecker and Lineated Woodpecker are quite similar in appearance and most people look to the facial markings to distinguish them. If the head is turned away or you don’t have a good look at the facial markings there is one quick aspect of GISS (general impression, shape and size) that helps distinguish them and it relates to a major difference between the Campephilus and Dryocopus woodpeckers (and one that helps us understand why such similar looking woodpeckers belong to different genera).

The Campephilus woodpeckers include many of the world’s largest woodpecker species and they have a neat trick to support their weight and large bodies. In addition to gripping with their toes and stiffened tail feathers, they also spread their trasometatarsus wide with the joint resting against the trunk as an extra support. The top two photos of a Pale-billed Woodpecker shows how this works on a vertical trunk (top left) and an angled branch (top right). Notice how the tarsus and “joint” rest against the trunk such that the bird appears to be resting on them (which many of us might think of this joint as a bird’s knee but it is technically the ankle). Even though the Dryocopus woodpeckers are almost as large, they perch in a more “normal” woodpecker fashion, gripping with their toes and using their tail as a brace as these Lineated Woodpeckers show on a vertical trunk (bottom left) and on an angled branch (bottom right). In each case, notice how the joint does not touch the tree and the tarsi are held at more of a 45 degree angle to the body and to the surface they are resting on (as opposed to resting on the surface as in the Pale-billed Woodpecker examples). This difference is visible from a distance and can be a useful identification clue in situations where lighting or distance makes it hard to observe plumage details with clarity.

To give a more complete, broader picture, following IOC taxonomy, there are six Dryocopus species: Black-bodied Woodpecker, Lineated Woodpecker, Pileated Woodpecker, White-bellied Woodpecker, Andaman Woodpecker and Black Woodpecker. There are 11 Campephilus species (all confined to the Americas), with the two largest presumed extinct: Powerful Woodpecker, Crimson-bellied Woodpecker, Red-necked Woodpecker, Robust Woodpecker, Crimson-crested Woodpecker, Pale-billed Woodpecker, Guayaquil Woodpecker, Cream-backed Woodpecker, Magellanic Woodpecker, Ivory-billed Woodpecker (presumed extinct) and Imperial Woodpecker (presumed extinct). Note that Helmeted Woodpecker has now been moved to the genus Celeus.

Saturday, April 2, 2016

The many faces of the devil - Stygian Owl (Asio stygius)

The collage below shows Stygian Owls (Asio stygius) from Sinaloa, Mexico (top left, top centre), Cuba (top right), São Paulo state Brazil (bottom left) and Quito, Ecuador (bottom centre and bottom right). This shows shows some of the variation in three of the six subspecies: the nominate subspecies in the bottom row (although some have argued that the southern Brazilian birds should be in the A. s. barberoi subspecies) is described in most literature, the A. s. lambi subspecies from western Mexican is said to be a little paler, and the A. s. siguapa subspecies from Cuba apparently smaller with whiter markings. You can judge for yourself from these photos.

With their dark, almost black, plumage and long, close-set ear-tufts (that look like horns), the Stygian Owl is arguably the most “diabolical” of owls. The Stygian Owl (Asio stygius), is named after the River Styx, which of course in Greek mythology was the gateway to the afterlife. Indeed, in part because of their nocturnal haunts and human-like faces, owls have a symbolism of death and/or the afterlife in many cultures from all around the world; but the Stygian Owl arguably best demonstrates that imagery. As with other owl species from around the world, this species faces persecution in areas where it is believed to be a witch or an evil spirit and the population on the island of Hispaniola (A. s. noctipetens) is considered vulnerable for that reason. Despite persecution based on fear, this is surely one of the most handsome little devils anyone could encounter on a dark night!

The Stygian Owl is a member of the genus Asio, related to the Long-eared Owl and Short-eared Owl that many of my North American, Asian and European friends will be familiar with. The Stygian Owl is a couple of inches larger than either of those two species but you can certainly see the resemblance; for example, note the close-set ear-tufts as opposed to the widely parted, sometimes sideways ear-tufts of Bubo (“eagle-owls” and “horned owls”). The Stygian Owl has a deep hooting call similar to Long-eared Owl except that the notes have a hint of a disyllabic slur and slide down the scale a little. Although thought to be mostly resident, there may be some nomadism or short migratory movements since there are at least two winter records in southern U.S.A.

Tuesday, March 1, 2016

MANITOBA NOCTURNAL OWL SURVEY 2016


In two short weeks it will be time to start surveying owls in Manitoba again! Some of you may be interested in joining this extremely popular survey. As you may know, Jim​ and Patsy Duncan created the Manitoba Nocturnal Owl Survey way back in 1991 and it was a first of its kind at the time. After 25 years of extraordinary service, Jim and Patsy have decided to hand over the coordination of the program to me and Bird Studies Canada​ (BSC) has built a portal at http://bsc-eoc.org/birdmon/mbowls/main.jsp to facilitate data entry. We are also working on some added features on the portal too; for example, take a look at http://bsc-eoc.org/birdmon/mbowls/submitdata.jsp to see your route. I hope you can continue to do your NOS route in 2016 in the usual manner – the only difference being that you should now send your results to me or, even better, sign up for a login to enter your data online directly (but don’t worry, if you want to submit paper forms you can continue to do so).

In addition to the new website I mentioned, the forms for the survey are still available at http://www.naturenorth.com/summer/creature/owl/owl_new/owl2005.html. If you are able to do a Nocturnal Owl Survey in 2016, could I ask you to drop me a line or give me a call just to let me know which routes you plan on doing. That would help me keep track of active and new routes. If you would like a new route, also get in touch. If you have not done a nocturnal owl survey before and are interested, please also get in touch. If there are enough interested new participants I may be able to organise a short informal workshop on identifying the calls of Manitoba owls (and a few "sound-alikes" such as Wilson's Snipe).

For those interested, the 2015 annual report is now available at http://www.naturenorth.com/summer/creature/owl/owl_new/1%20-%202015%20Manitoba's%20Owl%20Survey%20Annual%20Report%20-%20Final.pdf. In the report, Jim provides an overview of the history of the Manitoba NOS and talks about future direction. In addition, he provides a synopsis of a recent survey of owl surveyors by graduate student Christopher Ng that is well worth a read.

Happy owling everyone! Photo shows a southern Manitoba Great Gray Owl executing an in-flight turn (going back to where the vole hunting was better apparently).

Christian Artuso
 - - -
Christian Artuso, Ph.D.
Bird Studies Canada - Manitoba Program Manager
cartuso (AT) birdscanada (DOT) org

Monday, February 22, 2016

My Upcoming Talks & workshops

By popular demand, placing a list of my upcoming talks & workshops here (public ones only listed) and will update as required:

•   Owls of the World – February 23rd for Nature Manitoba (http://www.naturemanitoba.ca/?q=workshops/1086)
•   Bird of the Andes – March 3 at McNally Robinson (http://www.mcnallyrobinson.com/classroom-registration#.VsvUhdCyliw for any in this series)
•   Manitoba Raptors – March 10 at McNally Robinson
•   Manitoba Breeding Bird Atlas – March 12 at Oak Hammock Marsh Interpretive Centre for CMMN conference
•   Endangered Birds – March 17 at McNally Robinson
•   Manitoba Raptors – April 9 for La Rivière Raptor Festival
•   Returning Songbirds of Manitoba – May 14th at Oak Hammock for Migratory Bird Day
•   Birding by Ear: May 12th, FortWhyte Alive

Note that I had to cancel some May events this year due to unforeseen circumstances)

Contact me for details!  
 

Saturday, January 30, 2016

Resplendent Quetzal - a peculiar tail!

To some a deity or a deity's messanger, to some a national bird and even a currency, to others a source of wonder, the Resplendent Quetzal needs no introduction. Quetzals are a grouping of 6 species in two genera within the trogon family (Trogonidae): Eared Quetzal, Pavonine Quetzal, Golden-headed Quetzal, White-tipped Quetzal, Crested Quetzal and Resplendent Quetzal. Resplendent Quetzal is the only Mesoamerican quetzal species, with Eared Quetzal being North American and the others being South American. Resplendent Quetzal is by far the most famous for the male’s enormous tail that can be >75cm in length (this photo is of the costaricensis subspecies that has a slightly shorter tail than the nominate… believe it or not!). The funky head feathers and sickle-shaped wing coverts set against the waxy red belly add to the splendour. Resplendent Quetzal is not the only species in the world with a long tail but it is rather unique… Can you spot what is so unusual about the tail? Click on the photo to enlarge.



If you cannot figure out what is special about the tail in the above photo, this second photo may help:








If you still need help, notice how the tail feathers are black and normal length (the undertail coverts are white) and the long streamers fall over top of them. In short, it is NOT the tail feathers proper (the rectrices) but rather the uppertail coverts that are elongated. Many birds have long tails derived from elongated tail feathers but having elongated uppertail coverts to this extent is highly unusual. Coverts form the function of “covering” and creating the smooth surface so important for streamlining. Uppertail coverts cover the base of the tail so that the tail is more aerodynamic. Having a covert longer that the feathers it is supposed to be covering is quite unusual. There are four elongated uppertail coverts: two that are long and two that are extremely long!

Sunday, January 24, 2016

Owls of Costa Rica



On a recent trip to Costa Rica I saw 13 species of owl. This blog pot discusses those species that I managed to get good photos of, which is most of the country’s owls.


Bare-shanked Screech- Owl (Megascops clarkii), reddish-brown morph
The Bare-shanked Screech-Owl is endemic to the mountains of Costa Rica, Panama and extreme northwestern Colombia (from approx.. 900m – 3200m ASL but usually more common in the mid elevation cloud forest and humid forest). The first photo shows the bare shanks that gives the species its name. The second photo shows the wing droop display posture when delivering the territorial song. This is a red morph individual, which seemed more common in the parts of Costa Rica I visited than the dark brown morph.




Pacific Screech-Owl (Megascops cooperi)
The Pacific Screech-Owl occurs in a relatively narrow strip along the Pacific coast from southwestern Mexico (Oaxaca and Chiapas) to northwestern Costa Rica (mostly Guanacaste). This is a resident of dry forest types (also mangroves in some contexts), mostly in the lowlands but sometimes as high as 1000m ASL, although this individual photographed by Adrian Arroyo and myself in Monteverde, Costa Rica is at roughly 1300m ASL. Although common in its limited range, this is a poorly known species. This is one of the few species of Megascops that is not known to have a red morph (this follows the general pattern of higher prevalence of red morph birds in humid environments).



Vermiculated Screech-Owl complex in Costa Rica
Four photos showing:
* (Megascops vermiculatus), brown morph, Monteverde, Costa Rica,
* (Megascops guatemalae or vermiculatus), reddish-brown morph, Boca Tapada, Costa Rica.

It is worth stating firstly that there is little agreement on the species status of the various taxa within the Vermiculated Screech-Owl complex. Though some only recognise one or two species, others such as the IOC treat this group as five distinct species as follows:
* Middle American Screech-Owl (Megascops guatemalae)
* Vermiculated Screech-Owl (Megascops vermiculatus)
* Roraiman Screech-Owl (Megascops roraimae)
* Napo Screech-Owl (Megascops napensis)
* Choco Screech-Owl (Megascops centralis)

With the help of Adrian Mendez and Adrian Arroyo, I photographed this brown individual (first two photos) in Monteverde on the Pacific slope at approximately 1300 m ASL. I photographed this reddish-brown individual (third and fourth photos) near Boca Tapada in the Caribbean lowlands in the extreme north of the country. The issue for me was that the bird in Monteverde gave what I consider to be a typical song for M. vermiculatus, i.e. a very rapid trill that lasted approx. 8 seconds, whereas the bird I heard in Boca Tapada gave a very long trill that I timed at 20 seconds in duration and which struck me as more akin to M. guatemalae. Based on song along, I was inclined to think that two different species are present in Costa Rica (based on the split of the M. guatemalae complex into multiple species).

Nonetheless, the appearance of these birds did not match my expectations based on call. The bird from Monteverde, as you can see in these photos, is well marked with:
* a well-defined facial disk (suggests guatemalae according to the literature)
* prominent black streaking and cross barring below but not so strongly “vermiculated” (suggests guatemalae)
* prominent blackish crown streaks (may suggest guatemalae)
* weakly marked eyebrows (suggests vermiculatus)
* pale, somewhat greenish bill

The bird from Boca Tapada shows:
* a relatively weakly-defined facial disk (suggests vermiculatus)
* finely vermiculated underparts with little to no black markings (suggests vermiculatus)
* relatively prominent blackish crown streaks (may suggest guatemalae)
* weakly marked eyebrows (may suggests vermiculatus but not clear if relevant in this morph)
* pale, horn-coloured bill

The physical features of these birds therefore leave me with some doubts. Of course, the morphs are not the same so direct comparison is not really possible. In the end though, the long song of the bird in the Caribbean lowlands versus the short song of the bird on the Pacific slope suggests to me that the status of the screech-owls in Costa Rica warrants further investigation and clarification. This is something that some budding Costa Rican birders and ornithologists might like to investigate!






Crested Owl (Lophostrix cristata), pair at day roost
The unique (monotypic genus) and spectacular Crested Owl is always a special treat to observe. In this case, special thanks go to Jose (Cope) Arte who found this roosting pair of Crested Owls in the Caribbean lowlands of Costa Rica. You will notice that one of these owls has a cataract in one eye, although that does not seem to have weakened the pair bond between these two. Although it is very hard to tell in this particular photo, when observed from two angles, I felt the owl with the cataract was very slightly larger and hence probably female. The Crested Owl is a widespread, mostly lowland rainforest species, though sometimes found as high as 2,000 m ASL. The subspecies found in Central America is L. c. stricklandi. The slight colour difference between the pair was interesting and when I compare these individuals to Crested Owls I have seen in Mexico (click left arrow) they don’t seem to be quite as reddish in the face. The Central American birds are much darker than birds from Ecuador and Peru. Some have argued that may warrant a future split since the distribution is disjunct, with the Amazonian population being separated geographically from the Central America and northwestern (Pacific) South American birds.





Spectacled Owl (Pulsatrix perspicillata)
With thanks again to Cope Arte, I was delighted to get a chance to see this pair of Spectacled Owls on a day roost. Spectacled Owl is the largest (can reach 52 cm in length) and most widespread member of the genus Pulsatrix. This genus is confined to the Neotropics and has only three species (some authors split Spectacled Owl into two species, giving rise to a fourth species, but this is not widely accepted). The first photo is a crop showing one more closely to reveal the exceptionally beautiful pattern and and the second photo shows the pair together.




Black-and-white Owl (Strix nigrolineata)
* Taxonomic note: some authors place this species in the genus Ciccaba
The Black-and-white Owl is one of two Neotropical species with a unique jet black on white plumage, offset by yellow bare part colouration (possibly a third species exists, the San Isidro mystery owl). Black-and-white Owl is found in Central America (south from southernmost Mexico) and long the Pacific coast of northern South America (as far south as extreme northern Peru) and east across northernmost Venezuela. This is a large owl (females can measure as much as 40 cm in length) with a distinct guttural song. Despite their large size they seem to consume a lot of invertebrates. This bird came around the lights of the Laguna Lagarto lodge at night, seemingly looking for moths and perhaps also bats. Mikkola (2014) states that Black-and-white Owl and Black-banded Owl “clearly overlap in range in Colombia”; however, examination of range maps from a variety of sources suggests this is not the case.




Mottled Owl is a widespread species (unless you accept the proposed split of the Central American taxon) that occupies a wide variety of habitats and a considerable altitudinal range; for example I heard one at approximately 2400 m ASL on Volcán Irazú. I have found it to be very common in many parts of the Neotropics, with the possible exception of the Atlantic rainforests of Brazil, where a disjunct population occurs that seems more thinly distributed. This bird is more buffy below than others I have photographed in Mexico (possibly a question of colour morph).



Costa Rican Pygmy-Owl (Glaucidium costaricanum), brown and red morphs
The Costa Rican Pygmy-Owl is endemic to the mountains of Costa Rica and western Panama (rarely as low as 900m ASL but usually from ~1200 – 3400m ASL). For the most direct comparison I combined two photos into a collage showing the two colour morphs, red and brown. As discussed previously (see my previous post on polychromatism), colour morphs are common in the pygmy-owls (genus Glaucidum) and this species has two morphs. This taxon is now widely considered to be a full species; although it was formerly considered to be a subspecies of Andean Pygmy-Owl (genetic analysis suggests it is more closely related to Mountain Pygmy-Owl).



Ferruginous Pygmy-Owl (Glaucidium brasilianum), brown and red morphs
*Taxonomic note: some authors treat this taxon as Ridgway’s Wood-Owl (Glaucidium ridgwayi)  
The Ferruginous Pygmy-Owl is one of the most widespread of the Pygmy-owls (at least in the broadest sense as currently recognised by the IOC). In Costa Rica this species only occurs in the dry northwestern part of the country. This individual was photographed at Palo Verde in the early morning.



Unspotted Saw-whet Owl (Aegolius ridgwayi), Costa Rica
An avian enigma that is rarely seen, the Unspotted Saw-whet Owl (Aegolius ridgwayi) is a close relative of the Northern Saw-whet Owl and they have in the past been considered conspecific by some. I was absolutely delighted to spot the unspotted perched quietly in some liana vines beside a small road at approximately at 2400 m above sea level near Los Quetzales National Park, Costa Rica after working hard to try to hear one. Even better, I got to share my find with some ecstatic Costa Rican birders a couple of days later. Some taxonomists consider this to be the nominate subspecies, although others consider this species to be monotypic.

Unspotted Saw-whet Owl is the only extant species in the genus Aegolius from Mesoamerica. In addition there is one species from South America (Buff-fronted Owl) and two from North America (the Northern Saw-whet Owl and the Boreal Owl, which in addition to North America also occurs across northern Eurasia). An additional Caribbean species, the Bermuda Saw-whet Owl (Aegolius gradyi) is now considered extinct.

One of things I find most fascinating about the Unspottted Saw-whet Owl is that their adult plumage is extremely similar to the juvenal plumage of Northern Saw-whet Owl. Although there are many closely related bird species pairs where juvenal plumages or female plumages are very similar, and of course some where all adult plumages are similar, this seems like a rare case in the avian world where a species’ adult plumage closely resembles the distinct juvenal plumage of congenitors (making them rather Peter Pan-like in appearance, i.e. they give the impression of having never grown up). There are cases of individual birds from different taxa breeding in juvenal or subadult plumages but the evolutionary mechanism involved in this case remains unclear.


Thank you!
 
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