This New World blackbird (Icteridae) has got to be one of my all-time favourite birds to scan. Usually a few times a week (after you have been working with museum collections for a while and every species is not as exciting as it once was) you will open a draw and marvel at nature’s achievements. From its bright yellow tail to its simply fantastic multi-tonal face and beak, this bird is stunning. The joy at this species didn’t stop there, as not only did it look good but it scanned beautifully. It was done and dusted in 5 minutes flat. As someone who spends a large portion of their time 3D scanning birds this is quite the treat.
You can see how beautifully the scan of the Montezuma Oropendola or Great Oropendola came out by checking out our #BeakoftheWeek tweet.
— Mark My Bird (@MacrobirdEvol) 4 November 2015
What does it look like?
Say you are out for a stroll in Mexico and you see a beautiful avian specimen sitting in a nearby tree, how would you know if it is one of these guys? Being with a local bird guide would help, but apparently they are not always on hand. Knowing what they look like is always a good start, and by taking a scrutinising look at the picture below you’ll hopefully get your eye in for such an occasion.
Males are slightly bigger and heavier than females (m-47.5cm, ~500g; f-40cm, ~250g), and they do look similar so remembering this fact will be helpful in identifying the sex of what you are looking at. Starting from the bottom up, they have black legs, a yellow tail with black central feathers (retrices), dark chestnut body feathers and black head and neck feathers. Their faces have a patch of bare blue skin with a pink wattle under it and then the beak is half orange (from the tip to the centre) and half black (from the centre to where it meets the facial feathers).
As we like to say, you cannot guarantee that you will get to see any bird species that you set out to see, so knowing what it sounds like is a huge help when IDing bird species. Below is a sample of what they sound like, and you can head over to the fantastic Xeno Canto to listen to some more of their calls (it is Definitely worth having a listen to these as they are marvellous). Xeno Canto is a great way to spend a few minutes listening to random bird species if you find yourself at a loss.
Where can you find this bird?
This central american bird is found from the Atlantic slope of Eastern Mexico and South through Guatemala, Belize, Honduras, Nicaragua, Costa Rica down to Panama. The map below shows in more detail the range of this species.
This Oropendola is found in tropical forests and in forests along the banks of rivers (riparian forests) up to 1600m.
What does this species eat?
This species tends to forage in the upper canopy, rarely on the ground and it eats a wide variety of stuff. This ranges from the fruits of the gumbo-limbo and the Florida thatch palm, as well as the more familiar bananas and cacao, to nectar, insects and small invertebrates. They have also been known to eat bird species such as Lance-tailed Manakin (Chiroxiphia lanceolata) chicks.
Breeding occurs at different times across the range, but primarily from February to August. Their mating system is harem polygyny, where one male lives and mates with numerous females, but females only mate with one male. They live in colonies with a varying number of nests per colony, this can range from as low as 3 nests to as high as 172 nests, with the average being around 30-60, depending on where they are found.
There is a dominance hierarchy amongst males which influences the amount of time males spend in a colony. The more dominant male spends the most time in the colony, with lower ranking males visiting when he is absent. In DNA tests of 21 chicks, dominant or alpha males were found to sire 33% of chicks and beta-males 19% with lower-ranking and males displaying outside the colony siring the rest.
When displaying/showing off to females, males perform what could be deemed as a bow and is definitely worth checking out.
Females are responsible for nest building, usually 13-22m from the ground, with it taking 13-18 days to complete a nest. The nest is a “purse” 60-180cm long, that is open at the top, and formed from coarse plant fibres of eg banana/palm leaves. The female lines the nest with dry leaves, which she often cheekily steals from neighbouring nests.
You can see what the nest colonies look like in the picture below.
Two eggs are laid which, incubated by the female, take 17-18 days to hatch before the chicks then remain in the nest for around 35 days, being fed by the female. In Costa Rica it is reported that usually only one chick survives.
Good news on this front, with this species being listed as “Of Least Concern” on the IUCN redlist. It has range of around 450,000km2 and is seen as quite common in a lot of places across this range, which would be the reason for this lower degree of concern for this species. This is good news for colourful beak fans!
For further reading this week I have selected a paper that looks into the effect of sexual selection on song evolution in oropendolas and caciques.
For further interest, and i’ve gone off-piste here, I find the thought of using DNA to encode data fascinating and thought some of you might as well. If you do, head on over the Nature News to read some more.
. 2010. Montezuma Oropendola (Psarocolius montezuma), Neotropical Birds Online (T. S. Schulenberg, Editor). Ithaca: Cornell Lab of Ornithology; retrieved from Neotropical Birds Online: http://neotropical.birds.cornell.edu/portal/species/overview?p_p_spp=680076
BirdLife International (2016) Species factsheet:Psarocolius montezuma. Downloaded from http://www.birdlife.org on 31/08/2016.
BirdLife International. 2012. Psarocolius montezuma. The IUCN Red List of Threatened Species 2012: e.T22724004A39873355. http://dx.doi.org/10.2305/IUCN.UK.2012-1.RLTS.T22724004A39873355.en. Downloaded on 26 August 2016.
Fraga, R. (2016). Montezuma Oropendola (Psarocolius montezuma). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (retrieved from http://www.hbw.com/node/62242 on 26 August 2016).
Images and Videos
BirdLife International and NatureServe (2014) Bird Species Distribution Maps of the World. 2012. Psarocolius montezuma. The IUCN Red List of Threatened Species. Version 2016-1.
Peter Boesman, XC274124. Accessible at www.xeno-canto.org/274124.