OOooo Fishy, Fishy, Fishy, Fish!

This week I’m going to talk about one of two species of diurnal raptor which occurs on all 6 habitable continents (Antarctica being inhabitable to raptors). The other of course being Falco peregrinus (peregrine falcon) which I’ve covered on my second post, this time it is about a bird of prey commonly known as the osprey or fish eagle/hawk. Ospreys (Pandion haliaetus) is a monotypic species of raptor which feeds almost entirely on fish, both freshwater and salt water species usually between 100-300g (Ferguson-Lees and Christie, 2001). Although their range is large, the breeding range is almost entirely Holarctic and Australasian, and most populations are migratory (Ferguson-Lees and Christie, 2001).

Figure 1. Map of global distribution of Pandion haliaetus. Darker shades indicate areas which breeding occurs, resident or at least regular occurance throughout the year. Light shade indicate regular presence but does not breed. (Ferguson-Lees and Christie, 2001)

Genetically Pandionidae forms a clade with Sagittaridae (secretarybirds), and Accipitridae (hawks, eagles, old world vultures, kites etc.), Pandionidae being closer related to Accipitridae than to Sagittaridae (Nishida et al., 2014). However this being said, the karyotypes of the different families are very different, Nishida et al. (2014) suggests that 2 major episode of chromosome rearrangement occurred within the clade; fission of macrochromosomes occurred frequently in ancestral forms and a high frequency of microchromosomal fusions in the lineage of Pandionidae and Accipitridae.

Pandion haliaetus with prey fish, at Morro Strand State Beach near Azure Street, Morro Bay, CA (Baird, 2006)

Since I live in Australia, let’s have a closer look at the Australasian Ospreys (P.h.cristatus), this subspecies of osprey is distributed from Indonesia down to Tasmania along the coast (Dennis and Clancy, 2014, Ferguson-Lees and Christie, 2001). The main morphological difference between P.h.crisatus and its Northern Hemisphere counterparts is that they are generally 12 – 14% smaller for both sexes (Dennis and Clancy, 2014, Ferguson-Lees and Christie, 2001). The highest population density of P.h.cristatus is in the tropical coastline of Australia, mainly Northern Territory and Western Australia. Incidentally the abundance of osprey lowers where urban development and tourism infrastructures are more extensive (Dennis and Clancy, 2014).

P.h.cristatus feeding on perch at Coral Bay, Western Australia 

(User: Psylexic, 2007)

Interestingly people have had some interesting views on the osprey, like how the fish would surrender itself to the osprey belly up, a helpless prey against the raptor(Cocker and Mabey, 2005). This notion was even used by Shakespeare in one of his final tragedy Coriolanus:

“I think he'll be to Rome As is the osprey to the fish, who takes it By sovereignty of nature.” (Shakespeare, 2010).

On that note, I think that’s enough for today’s post.

BAIRD, M. L. 2006. Osprey with fish. Wikipedia: Mike Baird. 

COCKER, M. & MABEY, R. 2005. Birds britannica, Random House.

DENNIS, T. E. & CLANCY, G. P. 2014. The Status of the Osprey (Pandion haliaetus cristatus) in Australia. Journal of Raptor Research, 48, 408-414.

FERGUSON-LEES, J. & CHRISTIE, D. A. 2001. Raptors of the world, Houghton Mifflin Harcourt.

NISHIDA, C., ISHISHITA, S., YAMADA, K., GRIFFIN, D. K. & MATSUDA, Y. 2014. Dynamic Chromosome Reorganization in the Osprey (Pandion haliaetus, Pandionidae, Falconiformes): Relationship between Chromosome Size and the Chromosomal Distribution of Centromeric Repetitive DNA Sequences. Cytogenetic and Genome Research, 142, 179-189.

SHAKESPEARE, W. 2010. Coriolanus, Cambridge University Press.

USER: PSYLEXIC 2007. Pandion cristatus. Wikipedia.