Great tits join forces to defend neighbours' nests

Aug 21, 2012 By Tamera Jones
Great tits join forces to defend neighbours' nests
Nest-boxes with great tit chicks in the Wytham Woods.

Great tits appear to have what might be described as their own neighbourhood watch scheme, the latest research suggests.

Scientists have found that they'll readily join their neighbours when defending their against predators, but only the ones they know well. If they're not on such friendly terms – because the neighbours are very new to the area – they're much less likely to budge an inch.

This is the first time scientists have shown a conclusive link between familiarity among individuals and their propensity to join in mobbing predators. The findings may ultimately give clues about how cooperation and sociability evolved.

'The respond when they've had a longer relationship with their neighbour. This drives their inclination to join in mobbing,' says Ada Graboswka-Zhang from the University of Oxford, lead author of the report, published in Biology Letters.

Graboswka-Zhang and her colleagues analysed birds in Wytham Woods, Oxfordshire in the UK. Wytham Woods is owned by the University of Oxford and is probably the most heavily-studied woodland in the UK; all birds are fitted with British Trust for Ornithology rings to help identify them.

Great tits live in fairly dense woodland. Rather than recognising each other by sight, they're more likely to know each other's calls.

Their chicks are preyed upon by a whole range of predators. Great spotted woodpeckers pull them from nest boxes, and weasels can get into boxes to pilfer eggs and the tiniest chicks.

'Eight out of ten of these birds die in their first year, and half die between their first and second years,' says Graboswka-Zhang.

The birds do their best to defend their nests by mobbing predators. This involves repeatedly making alarm calls, swivelling on their perches, frequently hopping between perches, and sometimes making exaggerated flights.

But the more individuals that get involved in mobbing, the more likely they are to deter predators. Indeed, scientists noticed long ago that great tit neighbours unite to drive away predators. But exactly why neighbouring birds choose to risk their necks is the subject of heated debate.

Recent studies have led them to wonder if neighbouring birds get involved with mobbing because they know their neighbours will reciprocate when they themselves get into a sticky situation.

If this was true, then you'd expect long-term neighbours that have built a reputation for always being there to defend other birds' nests against to benefit.

Previous research led by Graboswka-Zhang showed that great tits that know their neighbours well tend to do better at raising their chicks.

'Joining in defending others' nests may be one of the mechanisms underlying the success of these ,' she says.

So Graboswka-Zhang and colleagues at the University of Oxford set out to test the idea that long-term familiarity between neighbours determines whether or not they cooperate.

They also wanted to know if the distance between nests affect neighbours' tendency to join in. Not just that, but does familiarity affect how much mobbing they're prepared to do?

They found that in the nests where the birds had been neighbours the year before, at least one neighbouring great tit joined the mob in 12 out of 16 trials. But in nests where birds hadn't been before, the birds didn't mob anywhere near as often - only two out of 16 trials.

They also found that even neighbouring birds whose nests are some distance away still come and join in the mobbing. And the degree of familiarity has no bearing on the intensity of mobbing behaviour.

'They might join in, because they know they won't be left to defend their nests alone when they're in need. On the other hand, the birds could be helping, because their nest might be the next one to be targeted,' she adds. 'They may themselves feel threatened.'

It's hard to say which explanation is right. 'Helping is an emotive word and suggests they're behaving altruistically, which they may not be doing at all. It might just be that they're joining the mobbing crowd for entirely selfish reasons,' explains Graboswka-Zhang.

'The next task is to look at the mechanism to see if we can tease these possible differences apart,' she adds.

Explore further: Lemurs match scent of a friend to sound of her voice

More information: M. Grabowska-Zhang, B. C. Sheldon and C. A. Hinde, Long-term familiarity promotes joining in neighbour nest defence, Biology Letters, Published online before print April 25, 2012, doi: 10.1098/rsbl.2012.0183

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User comments : 11

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Vendicar_Decarian
4.6 / 5 (11) Aug 21, 2012
Great tits are generally the smaller ones.

Although there are exceptions.

NotAsleep
4.3 / 5 (6) Aug 21, 2012
I'm glad great tits are getting better press coverage. It's a shame we don't see stories about great tits like these more often
trekgeek1
5 / 5 (4) Aug 21, 2012
They knew exactly what they were doing with that title, and I commend them. Also, if you type in "great tits" into Google image, you get a bunch of extra features left out of the article.

Great tits are generally the smaller ones.

Although there are exceptions.



I married an exceptional woman ;)
NotParker
3.4 / 5 (16) Aug 21, 2012
Did you know great tits have other bird relatives?

tits, chickadees, and titmice

There should be a chickadoubledee.
rockwolf1000
4 / 5 (4) Aug 21, 2012
Did you know great tits have other bird relatives?

tits, chickadees, and titmice

There should be a chickadoubledee.


WOW! You finally said something that made me laugh. At least not at you. 5 Stars
Estevan57
1.8 / 5 (30) Aug 21, 2012
As part of my neighborhood watch team, I always keep a lookout for Great tits.
Great titmice?
Too darned easy.
geokstr
2.1 / 5 (15) Aug 22, 2012
Great tits are generally the smaller ones.

Although there are exceptions.


I can't believe I enjoyed a VD comment enough to give him a 5. No bile, no vicious personal attacks.

But I see also that NotParker made a similar comment, and at least two of those on the left gave him zeros.
Vendicar_Decarian
4.2 / 5 (5) Aug 22, 2012
Personally, I have seen Great Tits break up marriages but never defend nests.
TheGhostofOtto1923
2.9 / 5 (23) Aug 25, 2012
As part of my neighborhood watch team, I always keep a lookout for Great tits.
Great titmice?
Too darned easy.
Hmmm. Esai emerges from silent attack mode to make a crude sexual comment. Couldnt resist eh? Your not gonna start posting gay porn links again are you? Hope not.
Estevan57
1.6 / 5 (28) Aug 25, 2012
Since ALL of the comments have repeated the title of the article including yours, what's your point? Just being bitchy? Constipated?

If you want gay porn go find it on your own.

No wonder you can't appreciate Great tits.
TheGhostofOtto1923
3 / 5 (24) Aug 25, 2012
Since ALL of the comments have repeated the title of the article including yours, what's your point? Just being bitchy? Constipated?

If you want gay porn go find it on your own.

No wonder you can't appreciate Great tits.
Jeez I hope your little niece doesnt read that. You know, the one you are paying to uprate yourself and downrate poor otto with multiple sockpuppets?

'Uncle esai said the T word mom!!' Should he really be paying me to read that??'

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