ML366124511

Age

Not specified

Sex

Not specified

Observation details

After carefully reviewing my photos and being familiar with Magnificent Frigatebird, it is evident to me and anyone else that knows frigatebirds that there is a reasonable amount of similarity between Great, Lesser, and Magnificent Frigatebirds - particularly adult males of these three species. and to make it more challenging, the individual I photographed today appears quite obviously to be indeed an adult male. To compound the situation further, as excruciatingly rare and unexpected as Great or Lesser Frigatebird would be, there are a combined approximate 10 records for the United States/Canada/Mexico (6 Great, 4 Lesser), which does not include island nesting locations off the west coast Mexico and northern Central America. There could be possibly be an additional record or two for either species, but the point is, as surreal as it may seem, they cannot be discounted completely, especially with a few records of Great within 515 miles of Las Vegas on the Central California in the not so distant past. So, as extraordinarily rare and highly unexpected this specimen was here today, we must realize the highly remote potential of these other Fregata species. With this in mind, after examining my photos and comparing them extensively and accordingly with photos from "Birds of the World" and other references, of all three species in question here, I feel confident in drawing conclusion that this individual fits best for Magnificent Frigatebird over the other species. Upfront, separation from adult male Lesser Frigatebird seems fairly straightforward, in that adult male Lesser(s) clearly have definitive and diagnostic pale axillaries (armpits so to speak), which appears to quickly eliminate "my" bird in the photos as a Lesser Frigatebird,, as the bird in my photos is entirely black (completely dark on the underside which was especially evident through binoculars). Secondly, as a rule I teach birders to not utilize 'size" n their identifications until they are experienced enough in the field to truly be able to compare species relative size in their head, and I feel this usually takes years of subtle species comparison. How many times do you hear new birders explaining how "big" or "small" a bird was that they saw recently, without understanding the challenges of "sizing" a bird in the field. Subsequently, this identification point in separating Lesser from Magnificent may seem more subjective and less factual, especially in that I have not observed Lesser Frigatebirds in the wild, but I have vast experience in estimating relative size in species - particularly those overhead. With this in mind, I would like to stress that the size difference between the two species is substantial. Whereas in all frigatebirds females are overall larger than males, we are dealing strictly relative to males of the species in question here - making any comparison relative to this discussion specifically. In brief, a male Magnificent frigatebird will always be larger than a Lesser Frigatebird as well as a Great Frigatebird - though that size difference for the latter would not really be substantial enough to utilize effectively in separating Greater from Magnificent overhead in the field. However, in the case of Lesser vs Magnificent, the difference is much more substantial. Most references place Magnificent in the range of almost twice the weight, 10 inches longer in body length, and upwards of 19 inches longer wingspan. A general measurement of Magnificent would put them at about +/- 90 inches in wingspan, and Lesser at +/- 70/71 inches. As for body length, about 40 inches compared to 30 inches. And weight/bulk, about 1.5 lbs heavier for the typical Magnificent compared to Lesser. In birders "laymen" terms, and as biologist for 35 years this would put the wingspan of Magnificent as longer than both North American Eagles, and would legitimately place it as one of the top 5 longest wingspans of regularly occurring North American species. In other words, what I am saying here is that it was clear to me (despite not having observed Lesser Frigatebird before), this bird unequivocally and absolutely was not in the size category of 30 inches in length and a 5ft'10" inch wingspan. Even at a quarter mile up, (and having seen hundreds if not thousands of Magnificent Frigatebirds in my life), the individual today was clearly massive - undoubtedly more indicative of Magnificent over Lesser Frigatebird. As for a comparison to Great Frigatebird, this is certainly a bit more tricky and challenging, and to be sure, I really do not have much to work with in differentiating the species as I did with Lesser for comparison. Though females and young can be more readily separated based on plumage characteristics, it is more challenging with regards to adult male Great and Magnificent Frigatebirds. Not to mention the sizes are much more similar and certainly not useful in this situation as they were with separating out Lesser. However, other than probability in itself (which is certainly not good in itself to rely on), it has been indicated in the literature that adult male Great Frigatebird "should" exhibit "pale scalloping in the axillaries", which this bird (particularly in photos 7 and 7A) clearly does not exhibit - which is clearly more consistent for Magnificent Frigatebird. Though the bird does exhibit a couple individual "non-black" feathers on the underside, this could be some overall normal wear, especially in light of where it wandered from (Sea of Cortez? Off of Western Mexico?) Another, important note that is useful is attempting to separate male Great and Magnificent Frigatebirds is the presence of a pale alar panel on the upperwing of male Great Frigatebirds. To be clear, though I did not secure a dorsal photograph of this individual fieldmark, I did obtain brief but very clear and diagnostic dorsal views of the bird as it briefly circled above HBVP, and it was substantially evident that this bird was "all dark" on the upperwing - it definitively lacked any pale or contrasting plumage of any kind on the upperwing. On one final note, it has been shown that foot color is also a diagnostic fieldmark with Magnificent having dark gray feet, and Great Frigatebird having pink feet, but I could not clearly distinguish this fieldmark due to the distance involved. In brief, based on the attached photos, the description and evidence provided here, as well as my experience with this species and other species over the last 35 years, I feel this bird is a Magnificent Frigatebird.

Technical information

Model

COOLPIX P900

ISO

100

Focal length

170 mm

Flash

Flash did not fire

f-stop

f/5.6

Shutter speed

1/800 sec

Dimensions

3485 pixels x 2416 pixels

Original file size

4.24 MB