Jungle Crow complex (1 Viewer)

I've got "Indochina" (except the north) included in the range for levaillantii, so I assume the birds in Bangkok/East Thailand are Eastern Jungle Crows as well.

Xenospiza said:

I've got "Indochina" (except the north) included in the range for levaillantii, so I assume the birds in Bangkok/East Thailand are Eastern Jungle Crows as well.

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Having been watching what the IOC now class as Corvus culminatus in Gujurat last week, it was evident that there were two kinds of bill shapes! One was decurved, and had the appearance of being glued directly to the head, and the other was an extended rough diamond shape, thickest at the middle. Calls appeared identical, but the first shape was predominant, the second seen only once, in the observed individuals in a loose flock of 14 birds at Khejideya. The second shape varied noticeably in size.
Is this known, or is it perhaps a symptom of some disease?
MJB

Is there any recent information on the distribution of Eastern Jungle and Large-billed Crows in Thailand. We're discussing it in the ID forum and there still appears to be much confusion!

But maybe it's perfectly clear and I'm just being dense!

Not Thailand but the geographic "boundary" between thw two "species" in Assam is alleged to be the Bramaputra (north / south thereof). Given that it takes a crow less than a minute to fly across this, I suspect that (any?) boundary is not a clear cut as suggested. However if you were dealing with Cupwings (for example), a river of this width might faciltate divergence...

cheers, alan

jacana said:

Is there any recent information on the distribution of Eastern Jungle and Large-billed Crows in Thailand.

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Not recent, but Dickinson et al 2004 (p101) states that Martens et al 2000 considers Corvus levaillantii to occur in "most of Thailand", with C macrorhynchos "seen as reaching further north than Prachuab and east through south-east Thailand into Indochina". But also comments: "Enough adult specimens from Burma, Thailand and Indochina should be re-examined to determine where macrorhynchos becomes levaillantii."
:h?:

Clear as mud then! Thanks guys

xeno-canto

This xeno-canto feature article by Mike Nelson is a useful synthesis of published information:

• Vocal variation and future splits of the Large-billed Crow complex.

Hokkaido/Sakhalin

Nakamura & Kryukov 2015. Phenetic analysis of skull reveals difference between Hokkaido and Sakhalin populations of the Jungle Crow Corvus macrorhynchos. Russ J Ornithol 24(1147): 1845–1858. [pdf]

Richard Klim said:

Nakamura & Kryukov 2015. Phenetic analysis of skull reveals difference between Hokkaido and Sakhalin populations of the Jungle Crow Corvus macrorhynchos. Russ J Ornithol 24(1147): 1845–1858. [pdf]

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Nakamura & Kryukov, 2016. Postglacial colonisation and diversification of the Jungle Crow (Corvus macrorhynchos) in its north-eastern frontier as revealed by morphological analysis. Journal of Ornithology. First online: 18 June 2016.

[abstract]

Corvus macrorhynchos intermedius

Farheena Iqbal, Qasim Ayub, Beng Kah Song, Robyn Wilson, Muhammad Fahim & Sadequr Rahman (2020) Sequence and phylogeny of the complete mitochondrial genome of the Himalayan jungle crow (Corvidae: Corvus macrorhynchos intermedius) from Pakistan, Mitochondrial DNA Part B, 5:1, 348-350, DOI: 10.1080/23802359.2019.1704637

Abstract:

Corvus macrorhynchos formerly referred to as the jungle crow or the large-billed crow is a polytypic species with unresolved taxonomy, comprising various subspecies widespread across South, Southeast, and East Asia. In this study, we report the complete mitogenome of one of these subspecies, Corvus macrorhynchos intermedius (Himalaya crow), from Pakistan. The mitochondrial genome is circular, 16,927 bp and contains typical animal mitochondrial genes (13 protein-coding genes, 2 ribosomal RNA, and 22 transfer RNA) and one non-coding region (D-loop) with a nucleotide content of A (30.6%), T (24.8%), G (14.8%), and C (29.8%). Phylogenetic analysis using the whole mitochondrial genome showed that C. m. intermedius and only reported subspecies Corvus macrorhynchos culminatus (Indian Jungle crow) are genetically distinct and it supports the recognition of the latter as a separate biospecies.

[pdf]