Author Archives: Museum Editor

Object of the Month – June 2021

A humpback whale leaping out of the sea. One flipper visible pointing left.

Humpback whale photographs taken by Barry Kaufmann-Wright in New Zealand, in 2013.

BK-W © Saffron Walden Museum

Image 1 of 5

BK-W © Saffron Walden Museum

All Images BK-W © Saffron Walden Museum

Barry took and kept over 72,000 photographs in his lifetime, almost all of wildlife and the countryside. Barry grew up in Buckinghamshire but his first job was at Jersey Zoo, working for the famous naturalist Gerald Durrell.
When he returned to the UK, Barry joined Essex police and was posted to Thaxted, where he began duties as Wildlife Crime Officer and, later, Wildlife Liaison Coordinator for Essex. His photographs from all over the world are a modern treasure in the Museum’s collection, which also includes two slide projectors which he used when giving talks – up to 250 times a year (that’s 5 per week)!
Barry’s wife Pat very kindly donated his photographs and equipment following his death in 2016.

Humpback whales live in oceans all over the world, except the far north of the Arctic Ocean and around Antarctica in the Southern Ocean, where the sea is covered in ice. Whales are mammals, so sea ice stops them coming to the surface to breathe air.
They are grouped into four major populations in the north Pacific Ocean, Atlantic Ocean, Southern Ocean and Indian Ocean. They usually migrate between summer and winter ranges, but there are year-round groups around Britain and Norway, and in the Arabian Sea between India and east Africa.

– They can grow up to 16 metres long
Humpbacks are one of the largest whale species. Females are slightly larger than males, usually up to 16m (50ft) long. They can weigh 30 tonnes – the same as 2½ double-decker buses.

This picture shows the size of a humpback whale compared to a human swimming next to it, and its long pectoral fins. Image: Jjw, CC BY-SA 4.0 via Wikimedia Commons

– They have ‘big wings’
The scientific name of the humpback whale, Megaptera novaeangliae, means ‘big wing of New England’. Their ‘big wings’ are their giant pectoral fins – one female had fins that were 6m (20ft) long, as tall as a giraffe!
The ‘New England’ part comes from where humpback whales were first discovered by European whalers, off the coast of New England in the far north-east of the USA.

– Each animal’s tail is unique
A whale’s tail is called a fluke, and has a wavy pattern along the rear edge. Like our fingerprints, this wavy pattern is unique to each whale and is an easy way to identify animals in a group.
Compare this image to Barry Kaufmann-Wright’s photograph of a humpback’s fluke, above.

Image: Terry Howard CC BY-SA 3.0 via Wikimedia Commons

– They use nets to catch fish
Humpbacks migrate between summer and winter ranges and only eat for 6 months of the year, in the cooler waters of their summer range. Hunting and eating for 22 hours a day means they can build up enough fat reserves to survive their winter breeding season without eating.
Some populations of humpbacks have learned to feed in groups using the ‘bubble net’ technique and use vocal calls to work together. The whales swim in circles below a school of fish, blowing bubbles from their blowholes to create a ‘net’ that the fish won’t swim through. When one whale gives a feeding call, all the whales swim upwards inside the net with their mouths open to catch the fish.

A humpback whale using the bubble net technique on its own. Image: Christin Khan, NOAA/NEFSC, Public domain, via Wikimedia Commons.

– They sieve their food
Humpbacks are one of a group of whale species called baleen whales, which have bony, comb-like plates inside their mouths. With a mouth full of water and food animals, baleen whales partly close their mouths, and push water out through the baleen plates using their tongue. The baleen lets the water through but keeps in food such as fish and krill, which the whale then swallows.

Baleen plates and bristles in the mouth of a young gray whale. Image: Marc Webber/USFWS, Public domain, via Wikimedia Commons

Whale ear bone, probably from  North Pacific right whale (Eubalaena japonica)

The North Pacific right whale is a baleen whale like the humpback.
This bone is the tympanic bulla and may have come from a North Pacific right whale. It’s a hollow shape but made of heavy, dense bone which helps sound resonate in the whale’s middle ear, inside the head. In life, it would have been attached to the petrosal bone, which has snapped off.

Smaller bones called the hammer, anvil and stirrup would sit inside the hollow space, and actually transmit the sound from the outer inner to the inner ear, just like in humans.

The North pacific right whale got its name because it is a large whale (up to 18m long but weighing 80 tons) with plenty of valuable blubber, it moved slowly, and would float after it was killed. It was the ‘right’ whale to go for because it was easy to catch and made lots of money for the whalers.

Image: John Durban (NOAA), Public domain, via Wikimedia Commons

More than 15,000 were killed by whalers in the 19th and 20th centuries. Today, estimates say there are fewer than 400 North Pacific right whales left, split between an eastern and a western population, making them the smallest known population of all whale species, As a whole, they are listed as Endangered on the IUCN red list, while the eastern population is Critically Endangered, with less than 40 animals.

Use this link to listen to a song about the dangers of whaling, based on the songwriter’s own experiences in Australia in the 1950s – www.swmuseumlearning.com/general-5

Object of the Month – February 2021

Water voles are probably best known from the character ‘Ratty’ from The Wind in the Willows. Recently described as “Britain’s fastest, declining mammal”, they are making a comeback thanks to careful wildlife management and the return of a locally extinct predator – the polecat.

Water vole © Saffron Walden Museum.

Water voles are about the same size as a brown rat, but with a furry, much shorter tail, and small ears. Today, they are a semi-aquatic mammal, relying heavily on streams and rivers for food and shelter – they use their teeth to dig burrows into steep banks to shelter and raise their young.

Do water voles need water?

But it wasn’t always this way. They don’t show any of the usual adaptations for a water-based mammal, such as webbed feet and a ‘keeled’ tail (flattened sideways but taller top-to-bottom), both of which make otters very strong swimmers.
In the 1500s, rewards for hunting ‘rats’ may actually have referred to ‘water voles’ that lived entirely on land. Their burrowing habits and herbivorous diet would have made them an agricultural pest, which would explain the rewards paid for hunting them. Modern water voles are always found on waterways, so any hunting must have succeeded in wiping out fully-terrestrial water voles.

A population vole-ercoaster

In the 1990s and early 2000s, the number of water voles in the UK plummeted, making them Britain’s fastest-declining mammal. Surveys of water vole territories in Essex showed that  81% of recent territories were still occupied in 1990, but by 2005, only 7.5% of territories were still occupied in certain areas.
Such a drastic decline couldn’t just be down to habitat loss, and they are resistant to pollution – water vole colonies live in the banks of streams which run from landfill sites along the Thames estuary, and on rubbish-choked streams near Rainham.

Studies by Essex Wildlife Trust showed that crashes in water vole numbers closely followed local increases in the number the invasive American mink. These animals are not native to the UK, and became established after escaping or being released from fur farms from the 1950s onwards. Mink will hunt water voles in their burrows and in water, and a female can destroy a water vole colony in one breeding season. The water vole’s usual predators only hunt on land, and are too big to fit in their burrows.

American mink. © Saffron Walden Museum.

Essex Wildlife Trust began work in 2007 to control mink numbers in key water vole strongholds, allowing water voles to recover, and spread. In 2012, more areas were put under mink control, and water vole colonies were relocated from sites destroyed by development along the Thames and M25. Surveys in 2013 showed that these colonies had survived and spread, with several new colonies established along the river Colne and its tributaries.

Ratty’s new best friends

Since 2000, wildlife surveys have found an ever-increasing number of polecats, a native predator which had been extinct in Essex for over 100 years. Polecats were hunted to near extinction across the UK by gamekeepers, who treated them as dangerous vermin, and they were also easily caught and killed in rabbit traps, which fell out of use in the 1950s. Polecats have probably spread into Essex from a targeted release in Hertfordshire in 1982-3.

Natural Sciences Officer, James Lumbard, with the skin of a recenltly-mounted polecat. The polecat was brought to the Museum after being found dead at the roadside. Image © Saffron Walden Museum.

Otter © Saffron Waledn Museum. This otter is on view in the Victorian Museum Workroom display when the Musuem is open.

Informal tracking and recording also suggests that the return of polecats may be helping water voles spread and recover more quickly, by reducing mink numbers. The same is true for otters, which are now returning to Essex, after being declared locally extinct in 1986. Both of these animals are native predators that rarely hunt water voles, but will compete with the American mink for food and territory, and are also big enough to hunt or kill mink. There are no studies to confirm it yet, but it could be very good news for water voles, and wildlife-lovers across Essex.

References

Are the otter and ​polecat combining to reduce mink numbers? East Anglian Daily Times, first published 31 March, 2019. Accessed 29.1.2021: https://www.eadt.co.uk/news/business/rise-in-polecats-and-otters-hit-mink-2562736

Mammals of Essex by John Dobson and Darren Tansley, 2014.

Object of the Month – October 2020

New Zealand Kiwi

We’ve been busy over the last few weeks moving the bird taxidermy from a temporary home back to their usual store. October’s object of the month is a mounted kiwi skin, probably of a little spotted kiwi (Apteryx owenii), the smallest of the five kiwi species.

A stuffed Little spotted kiwi sking, facing left, mounted on a 'naturalistic' base.

The little spotted kiwi in Saffron Walden Museum. © SWM

With strong, heavy legs and no wings, kiwis have evolved for life on the ground. They are nocturnal, dig burrows to nest in, and have stiff, hair-like outer feathers to withstand pushing through leaves and twigs. Unlike most birds they have keen hearing and a good sense of smell to help them find food, mostly earthworms and insects.

A page from a book with drawings showing the head, wing and strong feet of a kiwi.

Kiwis have ‘whiskers’ around their beak, stiff feathers and tiny wings, and strong feet for digging.
[Internet Archive Book Images / No restrictions]

Kiwi numbers have plummeted since Europeans arrived in New Zealand, bringing rats, stoats, pigs, cats, dogs, trophy hunting and habitat destruction. Kiwis grow and reproduce slowly and only thrive today on protected reserves, with intensive work to remove these threats. The indigenous Maori regard the kiwi as a taonga (treasure), and actively protect the birds across 230,000 hectares of land, about the same area as the national government’s Department of Conservation. Altogether, an area of land bigger than Essex is managed for kiwi conservation.

Coloured map of New Zealand showing distribution of kiwis at present day and before European colonisation.

Light green, current location of kiwis; Dark green, location of kiwis before European colonisation; Dark grey, kiwis never known here. [© New Zealand Department of Conservation]

Map with numbers and letters showing locations of Little spotted kiwi populations across New Zealand.

Little spotted kiwi reserves – Predator-free islands: 1, Hen Island; 2, Tiritiri Matangi; 3. Red Mercury Island; 4, Motuihe Island; 5, Kapiti Island; 6, Long Island; 7, Anchor Island; 8, Chalky Island
Mainland: A, Shakespear Open Sanctuary; B, Cape Sanctuary; C, Zealandia.
Michal Klajban / CC BY-SA 4.0

See the little spotted kiwi and find out more about kiwi species in our Object of the Month display when the museum re-opens soon.

More information
New Zealand Department of Conservation (DoC) –  Facts about kiwi: https://www.doc.govt.nz/nature/native-animals/birds/birds-a-z/kiwi/facts/
New Zealand DoC – Little Spotted Kiwi: https://www.doc.govt.nz/nature/native-animals/birds/birds-a-z/kiwi/little-spotted-kiwi/
New Zealand DoC – Kiwi: https://www.doc.govt.nz/nature/native-animals/birds/birds-a-z/kiwi/
Science Learning Hub – Conserving our native kiwi: https://www.sciencelearn.org.nz/resources/2784-conserving-our-native-kiwi
WWF New Zealand – Kiwi: https://www.wwf.org.nz/what_we_do/species/kiwi/

References

Internet Archive Book Images. ‘Features of kiwis’ Transactions and proceedings of the New Zealand Institute (1870). Internet Archive Book Images / No restrictions. Available from commons.wikimedia.org [Accessed 29.9.2020]

Michal Klajban. ‘Apteryx owenii – distribution map. CC BY-SA (https://creativecommons.org/licenses/by-sa/4.0). Available from commons.wikimedia.org [Accessed 29.2.2020]

New Zealand Department of Conservation. Kiwi Recovery Plan Summary Document 2018-2028. New Zealand Government, 2018. Available from https://www.doc.govt.nz/nature/native-animals/birds/birds-a-z/kiwi/docs-work/ [Accessed 29.9.2020]

Object of the Month – June 2020

June’s Object of the Month celebrates Volunteers’ Week. These fossils have been cleaned and recorded by two dedicated geology volunteers, helping to audit the thousands of fossils held in the Museum’s stores. The project is suspended at the moment, but we all look forward to getting back together when times are better.

These fossils are from the Red Crag layers, which are the reason Walton-on-the-Naze is famous for marine fossils. The sandy Red Crag rocks and fossils were laid down in the late Pliocene and early Pleistocene epochs between 3.3 and 2.5 million years ago, when a warm, shallow sea and bay covered most of Essex. The fossils have stained red-brown over time due to iron-rich water washing through the sandy rock.

The first fossil is a species of whelk, Neptunea contraria, which is still alive today (extant, rather than extinct). This species has an unusual left-spiral shell, hence the word contraria in its scientific name. Almost all species with a coiled shell have a right-hand spiral.

Neptunea contraria

Cardita senilis

Cardita senilis is a species of bivalve, a group which also includes oysters, mussels and scallops. These molluscs have a flattened body protected by two shells or valves joined by a hinge. A bulge near the hinge, called the umbo, is the oldest part of a growing shell, and is at the centre of the growth rings that can sometimes be seen on the surface.

Spinucella tetragona is an extinct species of predatory sea snail, in a group known as murex snails or rock snails. This species’ shells are highly ridged, but other extant species (such as Chicoreus aculeatus) have exaggerated and complicated patterns of spines on their shells, which makes them very popular with shell collectors.

Chicoreus a

Spinucella tetragona

Chicoreus aculeatus

Oyster: Ostrea species

Later Pleistocene fossils from Essex, such as the oyster, don’t really ‘belong’ here at all. They were brought south or churned up from older rocks by glaciers during the Pleistocene Ice Age, which lasted from 2.5 Mya to 12,000 years ago. They appear in glacial drift deposits left behind as the glaciers grew and shrank. This fossil of Chicoreus aculea is actually from the Jurassic period (201-145 Million years ago).

All images © Saffron Walden Museum, except C. aculeatus: H. Zell – Own work, CC BY-SA 3.0

Identification – flint, fossil sponge

Figure showing flint nodule from chalk

In Essex and south east England, almost every pebble on the beach and in gardens is flint. It’s a hard rock found in the Chalk, a soft, white, limestone layer that is up to 200m (600 ft) thick in north Essex and Cambridgeshire. In north west Essex, this chalk is between 90 million and 66 million years old and lies just below the soil, north of a line running from Stansted to Sudbury.

Diagram showing bedrock geology of Essex

Diagram showing the main bedrocks across a section of Essex. Chalk appears as the bedrock across northern Essex. Credit: reference 1.

Chalk started out as a thick mud on the floor of a tropical sea that covered most of Britain and north west Europe. This mud contained the remains of tiny sea creatures (plankton) which grew shells of calcium carbonate. When they died, these plankton and their shells fell to the sea floor to form a thick mud, which compacted into chalk over millions of years.

As it compacted, it squeezed out the seawater containing dissolved quartz, or silica (which comes from the skeletons of tiny sponges, a very simple animal).This silica was pushed out into gaps, cracks and burrows in the chalky mud to form nodules or layers of flint. These flints have a white outer layer (cortex), and are black inside. They can come in very complicated, bulging shapes, or with spikes, holes and cavities. Because of this, they can be easily confused with fossilised bones.

Figure showing flint nodule from chalk

An irregular flint nodule with a white cortex. Credit: reference 2.

Some flints do contain fossils, often urchins, or cockles or other small shellfish. Sometimes, the whole flint looks like fossil, and this may be because the silica that created it was forced into a hollow space in the hardening chalk which contained a sponge. Sponges are very simple animals which live on the sea floor. They still exist today, and the earliest known fossil sponges are  580 million years old.

The silica fills the gaps in the sponge’s skeleton and, over millions of years, the skeleton itself can dissolve away and be replaced by other minerals. This skeleton is a fossil, and the flint fills the spaces left by the soft parts of the animal after they rotted away.
Sponges are hollow tube or cone shapes and have no muscles, stomach, brain or nerves. They are filter feeders that catch bacteria and microscopic plants & animals from seawater that flows through tiny channels (pores) in their body.  Sponges are open at the top, and water currents flowing across the opening helps pull in water through the pores and remove it from the centre chamber, like wind blowing across a chimney.

Diagram showing water flow through a sponge's body

A simple diagram of a sponge’s body showing the pores in the sponge’s body, and the direction of water flow (blue arrows). Credit: reference 3.

Figure showing a living sponge

A living sponge, showing the typical hollow tube shape. Credit: reference 4.

The first sponge below is preserved in chalk and is a typical funnel shape. Some fossils may have a textured ring around the top, showing the rough pattern of the sponge’s surface and pores, like in the second photo.

Figure showing typical funnel shaped sponge

Fossil of a sponge (Ventriculites species) that lived in the Chalk sea. This sponge attached to the sediment with its branching roots. © SWM.

Figure showing rim imprint of a sponge's body in flint.

A flint nodule showing the imprint of the upper rim of a sponge’s body. Credit: reference 5

References

  1. Essex Bedrock, Essex Rock 1999. GeoEssex.org, retrieved 11:36, 24.4.2020
  2. © G Lucy. GeoEssex.org, retrieved 11:31, 24.4.2020
  3. Adapted from: Porifera_body_structures_01 By Philcha – Own work, CC BY-SA 3.0
  4. NOAA Photo Library reef3859 By Twilight Zone Expedition Team 2007, NOAA-OE. , Public Domain,
  5. Flint rim print. flint-paramoudra.com, retrieved 11:47, 24.4.2020

Identification – cattle hock bone

Photo of the calcaneus.

Cattle right-side calcaneus (heel bone)

The calcaneus in humans is the heel bone, and is the first point of contact with the floor when we walk. However, cattle are ‘nail-walkers’ – walking on the very tips of their toes with the rest of the foot held off the ground. This means the first joint from the ground on the hind leg is the ankle (hock), not the knee, which is why it bends in the opposite direction to our knee. The knee is further up the leg, almost hidden by the leg muscles, while the hip is very high up, just below the base of the tail.

Diagrom to show position of hock in cattle leg

The hock bone (calcaneus) is shown by no. 32 (bottom right). 31 shows the ankle joint and 30 shows the knuckles of the toes. 27 shows the knee joint (bottom middle). Image credit: reference 1.

The bovine foot has 15 bones, grouped into 7 tarsals (talus, calcaneus, and five others), 2 metatarsals (running from the tarsals to thethe two toes). These correspond to the 3rd and 4th metatarsals in human feet The big toe has the first metatarsal). The cow has 6 phalanges (three in each toe).
For comparison, humans have 26 foot bones, comprising 7 tarsals, 5 metatarsals (one leading to each toe) and 14 phalanges (two for the big toe and three for every other toe).

Diagrams showing skeletons of the cattle and human foot.

15-21 are the ankle bones, 23 and 24 are the metatarsals, and 26-28 show the three phalanges in each toe. The same bones are labelled in the human foot on the right. Image credits: references 2 and 3.

(The image above actually shows the front leg of a cow, with the wrist and not the ankle bones, but the other bones are generally the same.)

Photo of the calcaneus.

The original bone I was asked to ID. © Saffron Walden Museum.

In life, this cattle calcaneus is from the right hock and has the smooth side faces outward to the right, as in the photo above. The shaft of the bone is then pointing up and back, toward the tail of the animal, to form the distinctive point of the hock in the cow’s leg (no. 32 in the first diagram). The top of the bone  is the attachment point for the large muscles of the lower leg. These are the gastrocnemius and soleus, (the ‘calf muscles’ in humans).

Some of the more fragile edges of this calcaneus are missing, but you can still see the main features.

This photo is pretty much a close-up of the photo above, from the bottom end. © Saffron Walden Museum.

In the photo, the letter A shows a smooth articular surface for the 3rd and 4th metatarsals, and B is one of the articular surfaces with the talus. C is a dome-shaped articular surface for the lateral malleolus, a bone on the outer edge of the hock.  The roughened depression (D) in the centre of the plate is called the tarsal sinus, and is mirrored by a similar area on the talus. This cavity houses blood vessels, fat, nerves, and a series of ligaments which hold the tarsal bones together.
The talar shelf (E), is at the near end of the shaft, and helps support the talus bone which sits above it. There is also a groove (F) for the tendon of the flexor digitorum lateralis muscle, which bends the toes.

 The calf muscles which attach to the top of the bone help straighten the leg when walking and running, while the length of the bone acts as a lever to amplify their effect and increase make the movement more efficient This is especially important in animals such as cattle, whose ancestors and wild relatives migrate across continents and run to escape predators.

 – James Lumbard, Natural Sciences Officer.

 

References

1. Domestic_animals;_ _history_and_description_of_the_horse,_mule,_cattle,_sheep,_swine,_poultry,_and_farm_dogs,_(1858)_(14598393827)
By Internet Archive Book Images – https://www.flickr.com/photos/internetarchivebookimages/14598393827/Source book page: https://archive.org/stream/domesticanimalsh00alle/domesticanimalsh00alle#page/n51/mode/1up, No restrictions, https://commons.wikimedia.org/w/index.php?curid=44520464

2. Cattle hock skeleton diagram © https://www.dcfirst.com/cow_skeletal_anatomy_poster.html Accessed 31.3.2020.

3. BruceBlaus. :Blausen.com staff (2014). “Medical gallery of Blausen Medical 201”. WikiJournal of Medicine 1 (2). DOI:10.15347/wjm/2014.010. ISSN 2002-4436. / CC BY 3.0

Identification – Limonite

Yellow limonite on brown goethite.

Limonite (pronounced “lime-on-ite”) is an iron ore similar to the more well-known iron oxides haematite and magnetite. It often forms as existing deposits of these other minerals react with water in an oxidation reaction, turning the iron oxide into iron oxide-hydroxide. This interrupts the regular crystal structure and opens up microscopic gaps that trap other water molecules in positions where they can’t chemically react and bond with the iron atoms. Water which forms part of the molecular structure of in this way is called ‘water of crystallisation’.

Yellow limonite on brown goethite.

Limonite can be ground up to produce the pigment yellow ochre, famous from prehistoric cave paintings. This sample from the Museums’ mineral collection has yellow limonite on brown goethite, another form of iron hydroxide.
Image: © Saffron Walden Museum.

Scientifically, limonite does not meet the criteria of a ‘true’ mineral, which must have a consistent chemical formula and molecular crystal structure. Because limonite forms as a replacement for several other minerals, this means that the crystal structure is not consistent. Variations in the original mineral, the compounds dissolved in the water and the environment where it forms, also mean the relative amounts of iron oxide, iron hydroxide and water of crystallisation are not constant either.

Four small, rounded pieces of limonite

These pieces of limonite were originally pieces of the gemstone garnet. Iron-rich water filtering through these stones replaced the original garnet mineral with limonite, keeping the shape.
Image: Eurico Zimbres FGEL/UERJ CC BY-SA 2.0 br (Wikimedia Commons)

Limonite may be any colour from a rich yellow to a dark brown, and was used historically to make the yellow ochre pigment which is still produced in this way in Cyprus. Despite this variation in colour, an easy way to distinguish it from haematite is the ‘streak test’. This can be used to separate many minerals which may appear similar to the eye, by rubbing the mineral along a piece of un-glazed white porcelain. Limonite will leave a yellow-to-brown streak, whereas haematite produces a red streak.

Two forms of haematite leave a rusty red streak on ceramic, central.

Two different forms of haematite both leaving a rust-red streak.
Image: KarlaPanchuk [CC BY-SA 4.0] (Wikimedia Commons)

Deep red botryoidal (grape-like) haematite.

This is an easily-recognised form of iron oxide, haematite. The rounded, bulbous form is described as ‘botryoidal’, meaning grape-like in Greek.
Image: © Saffron Walden Museum

 – James Lumbard, Natural Sciences Officer.

Identification – Ammonite in sandstone

One of the most interesting parts of working in museums is helping people discover something new (and I usually learn something new myself). A really important way for museums to do their job as a welcoming public source of information is by identifying mystery objects that you might find on a walk, on a seaside holiday or even in your garden or attic.
Anyone can bring in an item for us to identify, for free, and you should have an answer within a few weeks. It might look a bit like this:

Ammonite in sandstone

This piece of stone is a Jurassic fine-grained sandstone or sandy limestone, which may be from the Lias Group rock unit found on the Dorset coast, although it has a sandier appearance and rougher texture than the rocks usually found in this formation. If it is from the Dorset Lias formation, the rock is roughly 195 to 200 million years old, and the fossils it contains would be a species of Promicroceras ammonite, which are common along the Dorset coast.

Fossil of a Promicroceras ammonite.
Image: Ammojoe CC BY-SA 3.0 (Wikimedia Commons)

The bristleworm, Polydora ciliata. Image: Yale Peabody Museum of Natural History [CC0] (Wikimedia Commons)

 

 

 

 

 

 

The surface pattern of pores in the rock was made much more recently. They were probably made by a species of Polydora worm, probably Polydora ciliata. P. ciliata is a small, rock- or shell-boring worm which can grow up to 30mm (1 1/8 in.) long, and is also known as a bristleworm.

P. ciliata burrows in stone. Image: Rosser1954 CC BY-SA 3.0 (Wikimedia Commons)

Bristleworms are thought to burrow into rock or shell by scraping away at the surface using specialised bristles on the fifth segment of its body, although it may also secrete chemicals such as weak acid to help. It digs a U-shaped burrow, which appears on rocks as distinctive small slots or a ‘sunglasses’ shape.

 – James Lumbard, Natural Sciences Officer.

 

Object of the Month – February 2020

Snowy owl from front left angle. White breast plumage, with brown bars to sides and legs. Brown spotted plumage on wings. Mounted on a wooden post. Against a dark grey background.
Snowy owl from front left angle. White breast plumage, with brown bars to sides and legs. Brown spotted plumage on wings. Mounted on a wooden post. Against a dark grey background.

A female snowy owl in the Museum’s collections. Image: © Saffron Walden Museum.

Snowy Owl

A female snowy owl, Bubo scandiacus. Female snowy owls have spotted and striped plumage (above), while the male bird is almost pure white (below, left). Snowy owls live in the Arctic Circle where they hunt for food over tundra and upland moors. These impressive predators eat lemmings and other rodents, birds and rabbits, and only very rarely visit the far north of Britain. This mounted skin was donated to Saffron Walden Museum in 2003 for the Education collection. It has come out of the store for Museums at Night, exhibitions and teaching sessions.

A snowy owl from front angle. Pure white plumage of male, with a few dark spots visble on left wing. Against a pale background.

A male snowy owl. Image: Barry Kaufmann-Wright © Saffron Walden Museum.

An eagle owl from front left angle. Tawny under-plumage with patterns of dark brown and pale grey in bars and stripes. Vivid orange iris to eyes, and large horn-like feathers. Perched on a wooden post. Against a snowy backdrop.

An eagle owl. Image: Kamil. Corrections Piotr_J [CC BY-SA 3.0] (Wikimedia Commons)

Did you know?

All living things have a common name, like ‘snowy owl’, and a scientific name. The scientific name is a combination of two words which are only used for that species. Humans are Homo sapiens, and our extinct close relatives the Neanderthals are Homo neanderthalensis. We are different species in the same genus, Homo.
But scientific names can change. In 2004, the scientific name of the snowy owl was changed from Nyctea scandiaca to Bubo scandiacus, after years of research on their genetics and the shape of their bones. This showed that they were more closely related to horned owls and eagle owls (above, right), and should use the same genus name, Bubo.

You can see the snowy owl as Object of the Month until 29th February.

Object of the Month – October 2019

This case is arranged to show which butterflies live in the Saffron Walden area today (left), and which are extinct (right).

These butterflies died off mainly because of changing land use in the 19th & 20th centuries. Butterflies such as the Adonis blue (1) and chalk-hill blue (2) prefer large areas of chalk wildflower meadow, grazed by sheep and cattle. However, much of this land was converted to crop farming in the 1800s and these specialist insects died off. Other changes, such as the end of coppicing in woodlands, removed the open wooded habitat that butterflies such as the grizzled skipper (3) thrive in.

Species like the purple emperor (4) and white admiral (5) feed on the sugary waste products from aphids (honeydew). Pollution from coal burning may have contributed to these butterflies’ extinction as the toxins could dissolve into the honeydew on the leaf surface.

However, 2019 has been a very good year for some impressive larger butterflies too, with lots of painted ladies (6) arriving in Britain from the Mediterranean as they migrate north. Protected roadside verges in Uttlesford also provide good chalk grassland habitat for species such as the small copper (7).

There is also some very good news for three ‘extinct’ species (green boxes in main image). The purple emperor (4) returned to Uttlesford about two years ago and has been seen in Shadwell Wood and Rowney Wood, two local Essex Wildlife Trust nature reserves. The silver-washed fritillary (8) was first seen again about five years ago and is now known from Shadwell Wood, Rowney Wood and Hatfield Forest. The marbled white (9) has also been spotted at Harrison Sayer and Noakes Grove nature reserves and along some protected roadside verges over the last two years. The return of these three species in protected areas of countryside and special habitats show just how important effective conservation efforts are in supporting our native wildlife.

You can learn more about how humans have affected local environments and wildlife, for bad and for good, in the Take Away the Walls exhibition until 3 November.
Find out how you can help local wildlife groups on the Discovery Centre noticeboard next to the stick insects, and in the Take Away the Walls exhibition.