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Hello, my name's Lindsay Turnbull and I'm an associate professor in the Department of Plant Sciences

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at the University of Oxford, and we're right in the middle of this very serious corona virus crisis right

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now. And my students are all stuck at home and we want to keep them in touch with biology

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and keep in touch with us. And so we're going to make a new series of videos and they're going to be called back

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garden biology.

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Hello and welcome to the 16th episode of Back Garden Biology. And it's going to be

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about garden birds. Well, it's going to expand out a little bit beyond garden birds because the famous

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really about foraging. So how do birds go about feeding, getting the energy they need?

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And what are the risks they run when they're doing that? And most of it is going to be about garden birds. Of course, a bit weird if it

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wasn't. And we're going to hear from Fredi, who is a pitch to student just finished in zoology.

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She's been studying some of the foraging tactics that garden birds use,

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particularly polluted. And great tips. She's been working up a while to Woods. We're going to hear a bit from her.

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But right at the end, we're going to hear from Annette Fire. She's a junior research fellow and she works

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on puffins with probably the world's best job. Right. And she looks at their foraging. They also

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have to grazi, find fish, feed their chicks and themselves. And that can be quite a complicated

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business. And she's got some great footage of them going about their fishing. So that's

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at the end to look forward to. And most of us have garden birds. Obviously, we don't live by the sea

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and we feed them food. Lots of us do. I've got some different kinds of food here. This is one of the foods

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that I feed my birds. These are sunflower seeds. They've had all the shells taken off them. And the birds much

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prefer that because they don't have to put so much energy in to two feedings.

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So energy is really important to birds. And if they have to spend a lot of time processing food, that makes

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it a lot less attractive to them. What's amazing is I also have these seeds. These are Niger

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seeds, and you can see they're really, really tiny. And you might imagine that that's not a

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good food for a bird. If you've got to pick up each one individually, that's going to be very time consuming.

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But goldfinches in particular, really love those those seeds. And I think they just sort of move them up

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in quite large quantities rather than picking them up one at a time. And certainly I see them sitting on my feet

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through the winter for hours on end, just gorging away on those. I mean, if you're a bit more adventurous as well as

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these more normal kinds of food, you might also want to consider buying something like this.

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These are freeze dried mealworms, but horrible looking. But Robins

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in particular really love them. And lots of gardens have a tame Robin My Robins,

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not very time. I was a bit disappointed. It comes out and sort of makes itself known to and it wants some food. But as

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soon as I come out to give it food, it disappears off. But a bit later in the programme, I want to show some footage

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from my mum's garden. And my mom has been feeding the birds for a long time and

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they have become incredibly tame. And she's built up generations of birds that have become incredibly time

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to put out mealworms in her garden. You aren't going to sit around long for things, come and get them. And actually,

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she doesn't just feed dried mealworms. She also feeds life worms

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and the birds go nuts for them. Okay, so we're gonna start off with Freddy talking a little bit about foraging,

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then coming back to my mum's garden and seeing the amazing birds there and then ending with Annette Fi

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and her puffins.

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One of the many ways we study somebody in White and Watts is we clip each individual

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with a little lacquering in which we put a trained

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tech. So to have a bird comes to a bird feeder. We get a record of its I.D.

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and a timestamp to feed a visit. And this allows us to analyse the forging behaviour

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and really great data. And so one of the things we found out is that birds differ

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in the way they use these features. They are binge eaters and grazes. The Bingy does other birds

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that come to the beach to eat as much as they possibly can and leave and come back at a later time

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with the other individuals rising throughout the day. And the grazing

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strategy is considered more risky because the birds repeatedly exposing themselves to

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potential predators. So if competition determines

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who can use the feeder and which way, then you would expect that individual to try to to

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reduce competition and basically spread out these multiple resources.

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We don't find evidence for this for individuals disputing themselves in such a way.

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Instead, we actually find that they move between food patches and more honest, coherent

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ways and tried to maintain cohesion with their members. And

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my own research actually showed that individuals would actively recruit other members

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to a food source when they have just discovered one. So you might ask why? Why would they

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recruit a potential competitor to a food source? So

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stretching the group brings benefits to each individual member by reducing

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the predation risk. So by just foraging with one other individuals and groups of two,

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I am already reducing my risk of being predated in case of a predation by 50 percent

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and a group of five. I my personal risk of being tonight is only a six.

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But you don't want to recruit too many other individuals because then

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competition again increases.

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So great. Thanks, Freddy. So a couple of weeks ago, when the lockdown eased and we were allowed to

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go and visit our parents again, I went up to Macclesfield, to my mom's gone, and you can see that

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her bird feeders are much bigger, more impressive than mine. There's two wonderful sunflower

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seed feeders here together. And these birds on those feeders are goldfinches.

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They're very distinctive with those red heads and those gold wing bars that give them the name.

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They've become quite common in gardens. They're one of those birds are doing better in gardens now near the Twittering,

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often as they go over. You can see they're also together and they often go around in flocks, especially

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in winter with other finches, too. That's what Fred he was talking about. It's reducing the risk of predation.

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Small birds are quite likely to get eaten by Svara Hawks. And Sparrowhawk comes to my mum's garden

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at least once a week to pick off one of those small birds. Now, this bird arriving

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at the sunflower seeds is something I never see in my garden, and that is a nuthatch. It almost

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looks a bit like a kingfisher, the build of the bird, a big head and a long, sharp beak.

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But it lives in woodlands and it loves to eat seeds and nuts and it can walk vertically down trees,

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which is a pretty impressive feat when you think about it. And speaking of woodpeckers, one of the other things my

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mum puts out to feed the birds is fat. It's plants fat. It's either coconut oil or peanut

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fat. And this is a great spotted woodpecker. They nest nearby. They bring their

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young every year to my mum's guard and the younger feeding on the fat as well. They're a bit nervous

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and causes before they start feeding. And you see this jackdaw arrives and scare's they are

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and it does this amazing defensive posture, but it's decided it doesn't want to fight with a jackdaw

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and it leaves know if the adult may have taken the Dardar on, but the baby wasn't prepared to. Now, remember, I told

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you that what's special about what my mum feeds as well as the life food. So here's me putting out some white

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wax worms and some mealworms all alive, the same number of eat. I was kind of interested

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in what the birds preferred. So I put them all out on the ground like this, waited for a couple of customers.

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Here's the first Robin arriving. You can see it does seem to further wax MS. That doesn't take very many, but it eats.

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Wanted to tie and eat them, swallows. It takes another one and then it disappears, mounts a bird feeding

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itself rather than taking food for its young. Little while later, a second Robin appeared.

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It does something different because it's trying to pick up every worm that it can see and it's sort of driving itself, Max.

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It keeps dropping them because it speaks for. But it just can't resist trying to pick up every one that it can see. And eventually

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a blue it just gets fed up of watching it and sweeps down just takes one from it. And my dad said he sometimes

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watch the Blackbird literally trying to stuff 20 of these worms into its beak

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and driving itself mad because it can't fit them all in. Now, finally, what I did is I put

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out a little bit, a little part, and I just filmed it empty and it took about three minutes. That's all for a huge

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part of these live worms to be totally emptied. I'm going to show you speeded up. My challenge is to ask

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you how many birds come, what species can you see? Can you even manage to count them? SPED

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up quite a lot. So I'll be impressed if you get this right.

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How did you get on? Well, I counted seven blue [INAUDIBLE]. Fifteen great [INAUDIBLE].

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Three robins. Four dunnarts. Just checking a map and a blackbird. Was

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that a partridge in a pear tree? I didn't say one of those. And if you enjoyed that music, that is the genuine

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sound of Prince Edward Island in Canada, where one of my peers, these students, Kristen Howard

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Norton, is comes from and he's there at the moment. He had to go back there during the lockdown. So

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thank you so much to him for doing that brilliant piece of fiddling. It's a piece called St. Anne's Skrill.

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If you thought you were seeing how sparrows, by the way, you weren't a Dunnock. It does look a little bit like

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a female house sparrow anyway. But they do kind of have a different way of walking and holding themselves.

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And they're not a sparrow at all, although they used to sometimes be called heads sparrows.

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Hello, I'm Annette Fay and I'm a seabird biologist. And today I'm going to tell you a little

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bit about sea birds and how they feed seabirds. A very different mother, birds,

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because they spend most of their lives at sea. And actually that means they have to feed on fish.

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Some of them will catch the fish from the surface just flying above the water and catching it as it appears.

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But others will actually dive sometimes very deep to catch prey.

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Now, feeding can be a challenge for seabirds, especially during the breeding season, because that's the

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moment where birds have to be on land to build a nest and where a cheque.

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But the fish remains at sea. So what they have to do is travel between the land and the sea

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to find fish for themselves and for the hungry chick. So how did they do this?

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Well, the first thing is that most of them are very good flyers. And so that means they can fly very long distances

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pretty quickly at a minimum cost. But another thing is that that chicks grow actually very

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slowly compared to garden birds whose chicks might stay in the nest for

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a couple of weeks. Seabird chicks might take months before they can leave the nest.

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And that's because they only fed maybe once or twice a day, sometimes actually less than once a day.

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And the parents have to make quite complex decisions when they want to decide what to feed

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because often near the breeding colonies where they are, they're not actually that much good

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food around. And usually the good feeding patches are further away. So imagine you have a small

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supermarket with not very well stocked shelves nearby, maybe five minutes away from your house

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or a much better, bigger supermarket with loads of choice in your food. But it's an hour's drive away.

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You can't always go to the one very far. It would just take too much time, especially if you have one hungry

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chick that you need to feed as often as you can. And so seabirds solve this problem

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by alternating very short trips to the local area, which is not

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so good. And that's to feed that chick as often as possible with occasional

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longer trips farther out where they get better food. And that's usually for themselves.

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And that is called dual foraging. Now, what's interesting is that actually

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both parents feed the chicks together. And we have noticed that the parents seem to alternate

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who's on which duty. So while one parents will be on short trips feeding the chick, the other one will go

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on a long trip to feed itself and then they'll swap. And that way, then once the chick is never not fed

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for a very long period of time. Now I see loads of different seabird

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species, but my favourite and the one I know most is the Atlantic Puffin. That's not

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hunting for food here. The very beautiful seabirds with a big, colourful beak. And you can find them

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all around the North Atlantic, including in the U.K. But we don't know very much

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about their feeding ecology by feeding ecology. I mean, everything has to do with feeding where

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they feed, what type of fish they eat and so on. So to try and find out more about

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this, I did a study where we use these really, really, really small trackers here. They only

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wear a couple of grams and we put these on the back of a fence and they'll measure for about a week

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whether birds are going to feed. And I also put some camera traps on the colony tops of the bird behaviour.

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When am I coming back to the nest to feed that chick? Now I'm going to share a few videos with you

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to show you what we found. So the first video illustrates the trips of a few puffins

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from Schoeman Islands in Wales going out to feed at sea. And every point on it, on the video

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is a different bird. And you can see these birds actually good feed quite far, even up to 75

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kilometres away. That's 150 kilometres and a single trip to get food either for themselves

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or for the chick. Now, the next video actually shows you a bird coming back to its nest

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with some fish in its big voice chick. And you can see it looks around and then it zooms into the bow very quickly.

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And you might wonder why that is. Well, the answer is on the next video, because actually there are goals around

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the colony and they're just waiting for the puffins to come back to scare them off and steal their fish.

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So the puffins when to come in, in their nests before the girls can get to them. And it's not just the big birds

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like those that do this. The next video I recorded in Iceland and actually there it was

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the very small Arctic tern. They were mobbing the puffins to try and steal their fish.

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And as you see on this video, they succeeded. Now, this really helped us understand more about

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the fitting ecology of puffins. But they will say one thing we do know, and that was what the adults who actually eating

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because we can only see were they carrying back to the chick. And to do this, we actually collecting some

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of their poop. And you can see on this video, that's how it works. And essentially what we did with this poop is we could

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look at the DNA in the faeces and identify what prey these were. And

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that's called DNA barcoding. And we could actually work out what the adult puffin had

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eaten based on this. And actually what we found was that mostly the adults were eating the same thing

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as that chicks. And so by combining all these techniques, the tracking

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with the camera traps and the DNA barcoding, we could finally get insight

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into the feeding behaviour of these seabirds. Okay.

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A huge thanks to Freddie. And to our net for sharing their research with us. I hope you enjoyed learning

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about that. And I hope you will be feeding the birds in your garden. You can still put food

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at all times of year. And the RSPB say that's okay. The parent birds know what they're

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doing and they generally won't feed their chicks anything inappropriate. I still have birds coming

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to my feeders. The young birds especially. They're fattening up around August time. You see

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them really drop off. And I don't quite know where they go if they go off to the countryside to law and feed on other foods

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and the gardens seem to be empty, but of course, they'll be back come autumn and winter. So get

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stocking up on food. So that's it from back garden biology this week. I'm not quite sure how many more of

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these I'm going to make now that lockdown's finished, but I do hope you've enjoyed watching them. If you've

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been a regular viewer.