Back to the ponds!

I returned this afternoon to the Summit Ponds (central Panama), after visiting the place last monday, this time accompanying Rosabel Miró who wanted to see the White-eyed Vireo reported there. The place was crowded with two groups of birders, one of them guided by Carlos Bethancourt himself (who reported the rare migrant in the first place, he is at the far left). They were more interested in the residents Lance-tailed Manakins, so we focused on finding the rare vireo (for Panama). Not even 10 minutes after our arrival, we found the White-eyed Vireo exactly in the same tangles where I left it last monday! In the meanwhile, both groups departed to the ponds. Since a year ago, the Autoridad del Canal de Panama (ACP) prohibited the entry to the ponds and we lost a nice birding area, but Carlos got a permission so he was able to visit the ponds and the old Gamboa road that passes through them... so I infiltrate the group! Before reaching the ponds, a male Gartered Trogon welcomed us by perching over the road and vocalizing for the delight of all the birders... specially those with photographic equipment. The yellow underparts and eye ring are enough to recognize this species in Panama. My photo is a little overexposed, but still you can have an idea of the beautiful color pattern that this creature have. At the ponds, everyone was busy watching the birds that live there. This is one of the most reliable sites to find Boat-billed Herons, and of course we found two of them quietly resting on a branch over the water... I barely saw one individual last year because I was unable to visit these ponds. Others birds, regular in the area, were Lesser Kiskadee, Amazon and Green Kingfishers and Prothonotary Warbler. Then, Carlos spotted a heron perched quietly close to the road. The excitement was evident when he revealed that he got an immature Agami Heron. Despite its youth, it exhibited the long and thin bill plus the very long neck characteristic of the species. The heron also exhibited some blue feathers, specially in the wings, and a contrasting light blue crown... simply amazing! You know is still a young bird because of its mostly brown plumage, with white throat and underparts. This is just my third Agami Heron, and my first in the Summit Ponds where it have been reported before. Carlos called Rosabel, who was still at the vireo spot showing it to her husband Karl who arrived later, and then he continue his way deep inside the road. We stayed admiring the heron, watching it fishing and moving along the fallen trunk. What a great experience. After a while, Rosabel received another phone call from Carlos. He and his group saw an adult Rufous Nightjar on a nest. He gave us the directions, and we eventually reached the place... Carlos was kind enough to come back in order to show us the bird, which was magnificently camouflaged with its surrounding, as you can see in the photo. What a great manner to end the day. Carlos, thank you again for all the pretty birds!

Mysterious nightjar in Pipeline road

During the last Christmas Bird Count, by the Mendoza river in Pipeline road (central Panama), I found an interesting nightjar perched atop a branch in the open, around 11:00 AM, probably a migrant Chuck-will's-widow (ChWW). All the team members (Venicio "Beny" Wilson, Rafael Luck and Osvaldo Quintero) were able to see the bird and to get photographs. The first thing we noticed was its posture, it was vertically perched like a potoo, showing well the undertail pattern but not as well the back nor the crown. We also noticed immediately its hugeness, looking definitively larger than the common nightjar usually found in Panama (Pauraque), approaching the size of a Common Potoo. Essentially, it was a cryptic patterned nightjar, mostly rufous-brown, with darker tones in the wing coverts and paler in the back. The underparts were mostly dark brown, with many rufous spots and fine dark vermiculations. The closed wings almost reached the tail tip, and the primaries were black with rufous barring. More interesting, at least the two external rectrices showed pale buffy tips and buffy white inner webs all the way to the undertail coverts (which were rufous with black barring), with the external webs boldy barred in buff and dark brown. The bird didn't vocalize nor move during the ten minutes or so that we watched it. Osvaldo and Rafael used their flashes with the camera... my own photo (digiscoped with my DSLR camera) was with natural light (however, the day was cloudy and the lights conditions were not the best). The Common Pauraque (above photo, a male) can be easily ruled out by tail pattern and lack of conspicuous chestnut cheeks (and less patterned shoulders and wing coverts). The really hard task is to rule out the Rufous Nightjar (RNj). The RNj is one of our resident nightjars, closely related to the ChWW. It prefers drier habitats in the Pacific slope of the country (second growths, thickets and forest edges), so a bird found deep inside a mature. wet forest in the Caribbean slope as this one will hardly be a RNj... in the other hand, the ChWW is a boreal migrant recorded in a wide variety of habitats in Panama, including mature wet forest, but also the same habitats preferred by the RNj and even residential areas with big trees. So, habitat favors ChWW... but birds doesn't read books, and there are some records of RNj in the Caribbean slope of the Canal area (although in cleared areas), so habitat alone is not enough to separate these birds. Another thing is the size. The ChWW is our largest nightjar, but we all know that size appreciation in the field is very subjective, and depends of maaaaany factors, including posture. About field marks, these two species are almost impossible to tell apart in the field, specially because we do not hear the characteristic call of the ChWW in its wintering grounds. In the hand, the ChWW have lateral filaments to the rictal bristles, absent in the RNj. Enlarge my photo of a RNj (above, from Summit Ponds, just across the continental divide in the Pacific slope of central Panama) and you will see the long rictal bristles arising from the base of its mouth. Now, call me crazy, but enlarge Osvaldo's photo (the first of this post)... although the resolution is not the best due to the distance, I can see that the rictal bristles look like a brush! Photo artifact? Lateral filaments? OK, it is hard to tell, so lets forget it. What about plumage marks. Some references list differences in the overall coloration, the color of the crown, the back and the throat to separate these two species in the field, but I have found that these field marks are not reliable after checking LOTS of ChWW's photos in the internet, and many RNj's photos as well (there not so many published photos of this species). This probably is due to many contributing factors, like age, sex and race (ssp) of the bird, the photographic settings, the light conditions, etc... but one characteristic seemed useful to correctly separate these two: the male's undertail pattern. In the ChWW, the white (or buff) of the inner webs is very extensive, more than that of the RNj, almost reaching the base of the feather and only skipping the tips. You can see this in Nate's photo, of The Drinking Bird blog, of a preserved ChWW specimen. Compare it with our bird. In the RNj, the white (or buff) is shorter, occupying only the distal half or third part of the feather. This difference is listed and/or illustrated by Ridgely & Gwynne (Birds of Panama), Ridgely & Greenfield (Birds of Ecuador), Hilty & Brown (Birds of Colombia, attached illustration), Garrigues & Dean (Birds of Costa Rica), just to mention a few! It is not exactly a field mark, because is very unlikely to watch this under normal field viewing conditions, so we were VERY lucky. I'm pretty convinced that our bird is a male Chuck-Will's-Widow based on tail pattern and habitat, and I want to know if you agree with me via the comments. Happy birding and Happy New Year by the way!