Friday mystery object #329 answer

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

20180503_165758-01.jpeg

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 #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:

lappet-faced_vulture.jpg

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.

514px-sarcoramphus_papa_-national_zoo_-washington_-usa-8a

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:

20171214_175153-01.jpeg

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.

mystery319

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 #317

For this week’s mystery object I’ve decided to stick with my favourite subject of skulls. This time it’s a bird from the Dead Zoo’s collection, that was in a drawer labelled “Unidentified” – let’s fix that!

mystery317

Any idea what species this skull belonged to? I have my suspicions, but I’d love to hear what you think.

As always, you can leave your clues, questions and suggestions in the comments section below. Have fun!

Friday mystery object #307 answer

Last week I gave you this specimen from the Irish Room of the Dead Zoo to try your hand at identifying:

mystery307

Now it’s not a particularly difficult species to identify for a keen birder, so I asked for cryptic clues to the identity, and I was not disappointed. Some suggestions were so cryptic I still haven’t managed to work them out!

First in was Jennifer Mccaire who quoted a brief line of poetry:

“…Thou hast no sorrow in thy song, No winter in thy year.”

This is a section of a poem published in 1770 by John Logan – the title being “Ode to the Cuckoo“. Now, it seems likely that Scottish born Logan wrote this about the Common Cuckoo Cuculus canorus Linnaeus, 1758 that breeds in Europe and which looks like this:

Common Cuckoo. Image by Chris Romeiks, 2011

Common Cuckoo. Image by Chris Romeiks, 2011

Clearly it’s a different bird (one which mimics the appearance of a female Sparrowhawk) and it’s not quite the same as the mystery object – although there are similarities. However, we must keep in mind that Jennifer is of the North American persuasion, so her thoughts on Cuckoos will probably veer towards the Black-billed Cuckoo or Yellow-billed Cuckoo (or maybe the Mangrove Cuckoo, but that’s not as widespread as the other two).

If you don’t know the difference between these two North American Cuckoos, here’s a handy illustration to help differentiate:

Black-billed Cuckoo (left), Yellow-billed Cuckoo (right). Watercolour by Louis Agassiz Fuertes between 1910 and 1914.

Black-billed Cuckoo (left), Yellow-billed Cuckoo (right). Watercolour by Louis Agassiz Fuertes between 1910 and 1914.

Continue reading

Friday mystery object #307

The last few months have been particularly busy for me as I’ve been working on a lighting project in the Irish Room of the Dead Zoo in Dublin, so I’ve not had much opportunity to dig out mystery objects and get good images for you to identify.

However, I have moved pretty much every specimen in the gallery and if you want to see how much stuff that entails there’s a 3D interactive map of the space available here (if you want to have a virtual tour of the whole museum check this out). All this moving means I’ve seen a lot of specimens, so here’s one of them for you to have a go at identifying:

mystery307

For a some of you this will be way too easy, so let’s have your best cryptic clues, hints and riddles as to what this is.

Have fun!

Friday mystery object #303 answer

Last week I gave you this mysterious bit of bone from the Thames to have a go at identifying:

mystery303b

A few ideas were put forward, but DrewM was spot on with the suggestion:

I think it’s the synsacrum of a bird, without the ilia fused – the foramina are for spinal nerves.

A synsacrum is a fused section of vertebrae including the sacrum (which is where the pelvis attaches to the spine). General opinion quickly agreed with that suggestion, but the taxonomic group that the synsacrum belongs to remained unguessed.

That is perhaps unsurprising, since it’s hard to find good comparative images of bird synsacra, especially with the hips and lateral (or side) bits knocked off and worn down.

chicken synsacrum

A Chicken synsacrum showing the section preserved in the mystery object

I had a go at looking through some of the comparative bird osteology collections at the Dead Zoo to get a feel for birds with a similar synsacral morphology.

The usual suspect for a bird bone found in the Thames (for me at least) is Chicken, since they’re so closely associated with humans and a lot of the bones washed up on the banks of the Thames are from butchery and food waste. The size was about right, but the vertebral centra (the middle bits) of the Chicken synsacrum become more narrow in the hip-line than in the mystery specimen.

Next I looked at ducks, whose centra taper more in the direction of the tail, then grebes whose whole synsacrum is more narrow overall:

grebe synsacrum

Synsacrum of a Great Crested Grebe

Eventually I made it to the gulls who seem to be a much better fit in terms of shape and the Herring Gull Larus argentatus Pontoppidan, 1763 was a good fit for size:

herring gull synsacrum

Herring Gull synsacrum

Now this doesn’t mean to say that the mystery object is certainly from a Herring Gull. I would want to have the object in my hand and comparative material available from several specimens to check the identification before being sure, but on the basis of the images that Keith Dunmall kindly provided, I think we’re in the right ball park.

More mysteries next week!