Friday mystery object #329 answer

Last week I gave you this mystery object to have a go at identifying:

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I expected most of the regulars to recognise that it’s a bird sternum, since I’ve talked about them quite a lot in the past – to the point of putting together images of a range of sterna from different bird families to help narrow down identifications:

However, this mystery sternum didn’t appear in my gallery, so I thought it would offer a bit of a challenge. Of course, that was before Wouter van Gestel (creator of the fantastic Skullsite resource) recognised it as being from a bird with a fascinating reproductive method based around carefully planned neglect. Yep, this is the sternum of a Common Cuckoo Cuculus canorus Linnaeus, 1758.

Cuckoos are visitors to Britain and Ireland, where they spend their summer holidays destroying the families of host birds (like Dunnocks and Reed Warblers) by removing an egg from the nests of a smaller species and laying their own egg. If the switch isn’t noticed (and most of the time it isn’t) the egg hatches and the Cuckoo chick turfs out the remaining eggs of the host birds, then demands vast quantities of food from the unwitting foster parents.

To help pull off this remarkable feat of irresponsible parenting (or brood parasitism as it’s more properly known), Cuckoos have become remarkable mimics. The male is similar in pattern, colour and flight style to a Eurasian Sparrowhawk – a notable predator of small songbirds.

Common cuckoo by Vogelartinfo, 2010

Common cuckoo in flight. Image by Vogelartinfo, 2010

He hangs around, scaring the host birds off their nest or acting as a distraction, so the female can sneak in and drop off an egg, which itself mimics the colouration of the host bird’s eggs. Different Cuckoos have different species of host bird that they specialise in parasitising, so their eggs are adapted to colour match those host eggs – which is important, since several host species have become wise to the Cuckoo’s tricks and will abandon or destroy any egg they recognise as different.

Reed Warbler nest with what looks like a sneaky impostor egg... Image by NottsExMiner, 2012

Reed Warbler nest with what looks like a sneaky impostor egg… Image by NottsExMiner, 2012

Bizarrely, after all this careful disguise and the danger of discovery, the Cuckoo chick that ends up being fed copious amounts of food by the foster parents rapidly becomes a behemoth that could by no means pass as the same species as its hosts, yet the foster parents carry on feeding it.

Reed Warbler feeding a Common Cuckoo chick in a nest. By Per Harald Olsen.

Reed Warbler feeding a Common Cuckoo chick in a nest. Image by Per Harald Olsen.

It’s remarkable to consider that the complex behaviours of Cuckoos must be entirely genetically determined, since they never meet their parents and never get to learn how to Cuckoo from another member of their own species.

With this as the mystery object, I was delighted last weekend when I heard my first Cuckoo of the year in County Clare – and I was even more excited when I saw one in flight. They may be sneaky destroyers of families, but they are also the heralds of summer in the countryside and it’s hard to not have a soft spot for their evocative call.

Friday mystery object #328

This Friday I have a feathery object for you to have a go at identifying. I stumbled across this specimen in the Dead Zoo stores and noticed it didn’t have a species identification (and the genus name also looked dubious to me). Any ideas what species this might be?

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As usual, you can put your thoughts, questions and suggestions in the comments box below. Cryptic clues are fun, poems are delightful but I do love a short story, so if you want to include the identification in a bit of short prose please give it a go!

Friday mystery object #320 answer

Happy New Year everyone!

Last week I gave you this skull to identify from the collections of the Dead Zoo in Dublin :

King Vulture Sarcoramphus papa (Linnaeus, 1758)

I also included the label, since it offers an interesting taxonomic twist.20171228_163420.jpg

If there’s one principle that I hope I’ve managed to convey over the last eight and half years of doing the Friday mystery object, is that you should never fully trust the label.

For starters, the number NMINH:2006.12.1698 could be misleading, as it reflects the year the specimen was catalogued rather than the year it was acquired. To explain, the NMI uses a very sensible numbering system that starts with the collection (NMINH = National Museum of Ireland Natural History) the year of registration (usually the year of acquisition) which allows you to know which register to look in, followed by the lot number (a sequential number reflecting how many acquisitions have come in that year), followed by the individual object number (the sequential number of that individual item in a particular lot). This system can have additional numbers added if necessary, such as if a piece of an individual object is removed for sampling.

However, some older objects were not registered when they entered the collection and as such they get a number that reflects the year they were documented rather than the year they were acquired. In this case the specimen was registered in 2006, but purchased from an auction of the collections of van Lidth de Jeude who died in 1863, as Nigel (the Dead Zoo Keeper) helpfully pointed out in the comments.

If the specimen had been accessioned and numbered on entering the collection back in the 1860’s then issues with the name would be expected since taxonomy constantly changes and old names are often wrong, but because of the new label and the 2006 date, you’d generally expect the name to be more up-to-date. However, it appears that the information on an old label was directly transcribed without being updated.

This is relevant because the name Orogyps auricularis is what we call a junior synonym, which means it has been used to describe a species that already has an older valid name. When this happens the older name takes precedence. In this case, Orogyps auricularis is a name applied in 1867 by Degland and Gerbe to a species that had already been named Vultur tracheliotos  by J.R. Forster in 1796 and which is now placed in a different genus, giving the name Torgos tracheliotos (Forster, 1796) – where the parentheses around the author name indicate that the scientific name has changed from the original version that was published by Forster.

These taxonomic and documentation twists are however rendered redundant as soon as you realise that this specimen is from a totally different species. In fact it’s not really anything like Torgos tracheliotos the Lappet-faced Vulture:

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Lappet-faced vulture

In fact, the only real similarity lies in the tip of the beak, which is a functional feature for tearing meat and which is convergent between the Old World Vultures and the New World Vultures. The Lappet-faced Vulture is an African species, while the mystery object has the distinctive deflection of the bill in the nasal region that indicates it’s a species from the Americas. This discrepancy in region was noted by palfreyman1414 and Gerard van den Brink.

Once you focus on the New World Vultures it becomes quite easy to make an identification, since there are only seven species and at 121mm this specimen is the third largest species after the condors – something easy to check on Skullsite. So well done to everyone who recognised the skull as belonging to the King Vulture Sarcoramphus papa (Linnaeus, 1758), especially palfreyman1414 who got there first.

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King Vulture by Eric Kilby, 2008

As you can see, not only was the taxonomy very out of date for this specimen, it was also completely wrong, because it was misidentified 150 years ago. This is why you should never fully trust labels – they will often be wrong and if you base research on misidentified specimens, that will be wrong too.

Another mystery specimen next week!

Friday mystery object #319 answer

Last week I gave you this unidentified skull from the Dead Zoo to have a go at identifying:

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It seems that everyone recognised this as the skull of a gull straightaway – the scars from the salt-glands on the top of the head and the shape of the bill combined to make it a bit of a give-away.

However, working out which species of gull is a bit more tricky, since many are remarkably similar in morphology, making size an important factor for consideration (I’ve talked about this before).

Now size is always a somewhat tricky thing to use for identification, for a variety of reasons. One is that there may be an overlap in size between species, another is that there will often be sexual dimorphism within a species that means you can’t just compare the length against another specimen of a species without considering sex. Then of course there’s age – if it’s not fully grown, it’s going to be smaller. Of course you also have to consider whether the bill sheath is present or absent, as this will add a few millimetres.

On top of all these issues, there’s the problem of how you actually measure the length in the first place. This is something I’ve researched in the past (link to pdf) and it’s a more significant problem than you might think. For example, when looking at the image I originally provided for the mystery object, it looks like the skull measures around 125mm, but if I chop the scale bar from the image, reduce the transparency to 50% and lay it directly over the centreline of the image of the specimen, it turns out to be around 128mm.

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Length is apparently 128mm

Add to this the fact that in the original image you can see a shadow under the scale bar, it becomes clear that the scale is somewhat elevated. This is because I raise the scale to be near the vertical midline of the specimen, to help keep everything in focus and limit the effect of parallax error. Normally this is good, because it allows a more accurate estimation of the length of a 3D specimen with a longest axis near the vertical midline, but in this case the longest part of the specimen is actually at the lowest part of the skull, so the elevated scale will make it look slightly shorter than it really is (due to the parallax error I was hoping to avoid…). This means that the specimen is probably closer to 129mm or 130mm in length.

With this in mind, the discussion about the lengths of various gull skulls between Wouter van Gestle (of Skullsite fame), Ric, Tim Dixon, Richard Lawrence, Gerard van den Brink and jennifermacaire needs to be reconsidered.

Richard Lawrence reported skull lengths for a variety of gulls as follows:

6x GBBG: 129 to 141 mm
2x LBBG: 117 mm
6x HG: 111 to 117mm
9x YLG: 111 to 126 mm ( larger with beak sheath though so would be smaller without).

So factoring in a length of 129-130mm for the mystery object it seems to fit well into the range for the Great Black-backed Gull Larus marinus Linnaeus, 1758. So well done to everyone who went for GBBG – this does seem most likely to be a skull from the largest gull species.

Great Black-backed Gull by Andreas Trepte, 2010

Great Black-backed Gull by Andreas Trepte, 2010

Friday mystery object #276 answer

Last week I gave you this specimen of “Pygostylia” to try your hand at identifying:

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It was a bit of a tricky one, since the alizarin preparation technique has left an adult bird looking like a newly hatched chick. However, even long-billed birds like snipe and curlews start out with a relatively short bill that grows as they mature. The confusion caused by the bill led to suggestions of Cormorant, Little Bittern, Ibis, Scolopacidae and Whimbrel.

There were a few key pointers to help identify the family that this bird belongs to, not least the tiny legs, although one of them has fallen off as noted by John D’Angelo in a neat cryptic clue.

There are a few other pointers – the back and top of the skull shows an interesting feature where the hyoid loops around, which is much clearer here:

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This is something I normally associate with woodpeckers, but you also see it in some other birds with very long tongues.

There is also a very short humerus, which is what clinched it for me:

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The long bill and tongue and short legs and humerus make this a hummingbird (as spotted by Henry McGhie on Twitter).

Unfortunately I don’t think there’s enough information visible on the specimen to confidently identify it to species or even genus, but I think it’s probably a member of the Trochilinae, possibly one of the Mangos in the genus Anthracothorax F. Boie, 1831.

I’d like to write more, but it’s NatSCA conference time and I’m having too much fun catching up with wonderful people!

Friday mystery object #145

Once again I have a genuine mystery object for you to identify this Friday. I have been going through some of the material from the old King’s College Collection in an effort to identify some material with no data that would be suitable for the Horniman’s handling collection.

I found this bird skull that I think would be ideal – I think I know what it is, but I need to make sure that I’m not mistaken and that it isn’t an important or rare species. I will check the identification myself and I will see if you all come to the same conclusions as me about what this is:

Please leave your comments and suggestions below and let’s see what we come up with!