Milner Centre for Evolution

Researchers and students blog about their activities in this unique cross-faculty research centre bridging biology, health and education.

Posts By: tt515

Bird supermoms

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by Tamás Székely

 

Motherhood is full of challenges. Mums need to look after not only themselves but also their offspring: mothers make sure the young have good food, healthy and develop well, and they need to shelter the young from harsh environment, nasty neighbours and hungry predators. In addition, mums need to keep a watchful eye on their partners: as an eminent neurobiologist puts it, from the mother’s point of view the husband is just yet another – not necessarily grown-up – offspring.

Blacksmith plover mothers fiercely protect their nest from snakes, monitor lizards and warthogs. Credit: Tamas Székely

Blacksmith plover mothers fiercely protect their nest from snakes, monitor lizards and warthogs. Credit: Tamas Székely

Birds stand out from the animal kingdom by having family life reminiscent of humans. In the vast majority of bird families the mother and the father share the domestic chores: they build the nest together and take turns keeping the eggs warm. Whilst sitting on a bunch of eggs does not sound hard work, if you have ever been locked up in a tiny room for months (like hornbill females do) – you know that it’s not fun – even though you got fed by your mate.

Once the babies pop out of eggs, the life of mums change: in about half of bird species they gather food around the nest and deliver them to the hungry chicks. Feeding 10-12 rapidly growing babies that seem to have insatiable demand is not a simple task: parents make hundreds of trips each day to bring the food home. In about 150 bird species the parents’ job is eased by their former offspring that stay at home and help rearing the next batch of offspring: instead of leaving home and seeking their own nest, these adolescents prefer to stay put. Indeed, in these cooperatively breeding species several generation live under the same roof – as humans did for millennia.

Southern Hornbill

Female hornbills, including the southern yellow-billed hornbills, seal themselves inside a large cavity by blocking the entry with mud. Whilst she incubates the eggs and rears the young, the male provides food for the whole family. Credit: Tamas Székely

In the other half of bird species the babies are lot more independent from start. In plovers, quails, rails and grouse the chicks start feeding themselves shortly after hatching from the eggs. In some species this means picking seeds from the ground whereas in others the chicks catch agile prey such as flies and tiny midges. This is one of the amazing aspects of bird life: this feat corresponds to a human baby catching fast running lizards at just a  few days old.

In nearly all bird species, however, the mums keep a watchful eye whilst the offspring develop. It’s a dangerous life out there: the world is full of snakes, raptors and carnivores that seek out the ever-growing chicks. Once a predator shows up around the nest, mum steps in: she warns her babies to keep silent whilst she is luring the predator away from the nest by pretending she is injured and thus an easy prey to catch. There are many unsung heroines here: lapwings, terns and skuas attack chick-hungry predators that are a hundred times  larger than themselves, and more often than not, their vicious attacks force the intruder to back off.

So which bird species has the supermoms? It’s probably one of the 200 species of ducks, grouse, hummingbirds and songbirds where only the female does all parental chores: she works immensely hard to nurture, protect and teach her offspring so that her fledged young are prepared for the hard life that’s out there. But when the going gets really tough and breeding takes place in a superharsh environment such as in blistering deserts or in freezing barren valleys of Antarctica where a single parent is unable to cope with all pressures, even supermoms need someone to share the chores.

 

For details of Professor Tamás Székely’s research on bird behaviour and ecology see  http://www.bath.ac.uk/bio-sci/contacts/academics/tamas_szekely/

 

Full house Darwin Day Lecture

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This year's Darwin day lecture was delivered by Professor Nick Davies FRS (Cambridge University). In his talk, entitled ‘Cuckoo – cheating by nature’, Prof Davies described one of nature’s most intriguing stories to a packed lecture theatre at the Bath Royal Literary and Scientific Institution. Captivating photographic and video footage showed how some cuckoo species lay their eggs in the nests of other birds and how little warblers are tricked into feeding enormous cuckoo chicks. In his talk, Prof Davies described how 30 years of elegant field experiments have revealed a continuing evolutionary arms race in which escalating host defences have selected for remarkable cuckoo trickery, including different guises in female cuckoos, forgeries of host eggs and manipulative begging by cuckoo chicks. This is a fascinating corner of Darwin's "entangled bank" where organisms are continually adapting to keep up with changes in their rivals. Many thanks to all those who helped to make this event such a great success.

Darwin_day_image1

 

Darwin’s 208th birthday was celebrated with a children’s workshop on Evolution at BRLSI

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Yesterday was the 208th anniversary of Charles Darwin’s birthday, and what better way to celebrate it, than to children learn about natural selection, sing happy birthday to Darwin and eat some delicious cake?

cake

The Bath Royal Literary and Scientific Institution (BRLSI) very kindly hosted Dr. Paula Kover (a reader in the Milner Centre for Evolution), Lucy Eaton, Lauren  and Amy  (final year Biology undergraduates doing research in science education) to run a workshop on Inheritance and evolution, called “The evolution show”. The children, volunteers and us had a great time, playing Chinese whispers with DNA sequence to learn about mutation, building birds and seeing how mutation and inheritance can make the bird become better at flying with the help of natural selection. The children loved seeing the tree of life, that shows the evolutionary relationship among all major groups of organisms, and discover that a T.rex barbecue was likely to taste like chicken!

Organizing workshops for young children (audience were 8 to 10 years old) is always a big challenge, because it needs to make evolution accessible and fun.  This time, it involved a lot of last-minute laminating, photo copying, and a mad dash around all the local supermarkets for numbered candles (Have they gone out of fashion?).  But it was all worth it, since 69% of the children attending the workshop gave us a score of 9 out of 10,  or higher.  Also, the undergraduate students that helped had a good experience, and are ready for some more teaching of evolution to young kids in primary schools this term.

bird

Measuring how far the bird flew.

fossils

Digging for fossils

trees

Exploring evolutionary trees

For more information on educational resources run by the Milner Centre for Evolution see here. And  Dr. Paula Kover also offers a wealth of resources for primary schools - see here.