Monday, December 29, 2014

Do Birds Smell?

It’s a question I asked myself a number of years ago when noting how long it took for birds to discover new sources of food, in particular the introduction of bird feeders where none had been used previously. 

Birds were always thought to have a very poor sense of smell. But most vultures and many scavenging seabirds locate their food by smell. Any birder who has been on a pelagic trip to see seabirds up close will be familiar with the practice of chucking overboard buckets of “chum” or “rubby dubby”, to lure shearwaters and petrels close to the boat. Scientists believe that other birds, e.g. homing pigeons, may use familiar odours in finding their way home or use their sense of smell during migratory journeys. Think about the various odours given off to overflying birds by different places, e.g. pine forest or ancient deciduous woodland, saline or fresh water, the urban jungle or the countryside. 

Egyptian Vulture

Manx Shearwater

A recent Dutch study determined that Great Tits found and located apple trees with winter moth infestations and big concentrations of caterpillars larvae by smell rather than sight. Tit species eat large numbers of insect larvae particularly during their breeding seasons when they feed them to their young, timing their breeding to do so. Trees benefit from the protection offered by birds removing larvae that would otherwise go on to eat the leaves and perhaps impact on tree growth and productivity. 

Great Tit

The Dutch experiments were designed to remove other possible ways in which the Great Tits might detect the winter moth larvae. The researchers removed the caterpillars, removed leaves with holes and even took away signs of ‘caterpillar poo’, ensuring no visual clues were left for the birds to locate the infested trees. Despite these measures the Great Tits repeatedly found the trees with larvae infestations. The results were clear, even when they couldn’t see the trees, the Great Tits homed in on trees with winter moth infestations when they could smell them. 

The researchers believe the trees gave off chemicals which birds can detect by smell to alert them to infestation. It has long been known that many plants attract insects using smells and benefit from the relationships as a result, but this is the first time they have been shown to attract birds in the same way. More research is needed to determine which chemicals are involved but infested trees were found to release more of a chemical responsible for the “green” smell of apples. 

Most bird feeders use metal/plastic tubes or wire mesh to make the food highly visible to birds and we naturally assume that birds start to use our bird feeders because they locate food via their keen eyesight. My new niger seed feeders arrived today, replacements for ones recently stolen from a ringing site. At first glance the design looks improbable and unlikely to work as the feeding holes are tiny. When the stainless steel cylinder is filled with niger, the seed is virtually invisible with just the tiniest point of an individual seed poking through odd holes. 

Niger feeders

Nevertheless I experimented with this design of feeder a number of years ago and found them to be highly successful in attracting Goldfinches very quickly and I attributed this to the birds’ ability to smell the niger. 

At lunchtime I took the new feeders to Oakenclough with fingers crossed that Scrooge doesn’t sniff them out before our ringing session which may well be tomorrow.

Goldfinch

Here’s an experiment anyone can try at home. Buy a sealed bag of niger seed, Guizotia abyssinica, open the bag and stick your nose in it. Then inhale and enjoy the sweet, oily, nutty fragrance which brings in those Goldfinches. 

No, there’s is no doubt in my mind that birds and in particular Goldfinches have well developed olfactory senses, probably as good as our own. 

Now you must excuse me. I’m sure that from the kitchen I can detect the unmistakable aroma of a curry cooking in the oven and I'm ready for a bite to eat. 


31 comments:

Bob Bushell said...

Brilliant showing, the best are the Manx Shearwater and lovely Goldfinch. Perfect photos.

David Gascoigne said...

It's an interesting hypothesis - or perhaps it is no longer a mere hypothesis. Conventional thought is that most avian species have poorly developed olfactory systems, but perhaps some species, like the Great Tits you cite above, have specialized receptors to zero in on certain odours which convey benefit in the form of a rich food supply. I will have to do a little more research! In the meantime I hope that your curry amply rewarded your own discerning sense of smell.

mick said...

Thanks for a very interesting post. Your photos are always great but I especially like the Great Tit.

Ileana said...

Very interesting post and nice photos!

eileeninmd said...

Interesting post, Phil! Awesome photos too. The Goldfinch is one of my favorites.. Happy Birding, have a great week ahead!

TexWisGirl said...

as you said, i hope the birds find them and the thief leaves them alone!

EG CameraGirl said...

Truly interesting! I've often wondered how birds locate feeders so easily!

Sylvia K said...

Terrific post and I feel the same as the others and do hope the thief leaves them alone! I do love your photos!! Have a great week and a very Happy New Year, Phil!!

Andrew Fulton said...

Another good read Phil.
I am so lucky to have plenty of Goldfinches feeding all year round in my garden on niger seed and sunflower hearts... by the way now my partner Mandy has seen your "pink" feeders she wants one lol.

Cynthia said...

Interesting. I've always heard that birds find feeders by sight. However they get here, I sure do enjoy having them visit my feeders, especially in the bleak winter.

Linda said...

Fascinating and informative, Phil, and your photos are lovely.

Karen Hayward-King said...

Great photos and a really interesting post. I'd always presumed,fro watching their behavior,that birds had a sense of smell..

Christian Perrin said...

Very interesting post, Phil!

I can't think of a good evolutionary reason as to why birds would be less capable in the olfactory department than their dinosaur ancestors. How would a sense of smell become inconsequential to their lifestyle? Surely most active creatures are aided by that sense.

We have lots of nectivorous birds in Australia and the trees that rely on them make scents so strong that even us disengaged humans can smell them. Presumably, this is at least partially for the benefit of the birds also?

Adam Jones said...

A great post Phil. It's not something I've ever thought about, but with a new window feeder still waiting for it's first avian visitor, I am now intrigued.

Margaret Adamson said...

Hi Phil. A very interesting post and I think if a gun was at my head I would agree with you. I often think we know so little about the birds, so much more to learn about them. Happy New Year. To you and may 2015 be a good year for You.

Fun60 said...

Really interesting post. Must confess I've never thought about birds having much sense of smell just assumed they have an excellent sense of sight.

Germán Ibarra Zorrilla said...

Bonito post, como siempre. Los mejores deseos para 2015, saludos desde España.

David Gascoigne said...

I am interested in Christian's comment above. I am no expert in the olfactory prowess of dinosaurs, and I have virtually no literature on my shelves, but if I dig back into the dark recesses of my mind to the days when I studied some of this stuff, I don't recall dinosaurs as being especially noted for a robust sense of smell. Ergo, if birds have inherited their odour-detecting ability from their ancient reptilian ancestors, it would make sense that they are not, in fact, well-equipped in this area.

alicesg said...

Beautiful to watch the birds in nature. Here wishing you and your family a very Happy New Year 2015.

Mama Zen said...

That's fascinating!

Jennifer A. Jilks said...

I learn so much from people like yourself!
I hope your curry tasted as good as it smelled!
(ツ) from Cottage Country Ontario , ON, Canada!

Neil said...

Interesting post. Happy New Year.

Margaret Adamson said...

Just thought you would like to know the vegetable in my post yesterday is New Zealand Yam.

bettyl-NZ said...

It's fascinating how much we keep learning about animals all around us. We have some of your European Goldfinches here in New Zealand but they prefer to gather food with the cows over a bird feeder in our garden. I guess my seeds don't smell as much as the cow poo!!

Irma said...

This is an interesting message.
I am also sure that birds can smell good.
The pictures are really great, my compliments Phil.
Best regards, Irma

Stuart Price said...

I'm sure gulls smell. Especially after scrabbling around rubbish tips.

Happy New year Phil..............

Marie said...

Wonderful post! really interesting! I never thought about if birds could smell or not. Fascinating. I bet they smell the sugar in my hummingbird feeders...check out next week's post for more of an explanation on that. :-) I sure hope Scrooge doesn't take your new feeders!

Chris Rohrer said...

I wondered that myself a while back and have come to the same conclusions. Birds do smell. Once feeders, etc are established they will watch when I put up food and also color is another factor with our hummingbirds. So like everything, it's a combo, but I highly suspect that many birds have some degree of smell. Hope your curry was delicious!

Phyllis Oller said...

I`ve always believed that birds find food & water by sight, especially water.Who really knows? your photos are awesome as always & you made us think...happy new year!phyllis

Wally Jones said...

Once again, "Another Bird Blog" is on the leading edge of avian science!

Some studies indicate certain species have larger "olfactory bulbs", a part of a bird's brain used to detect odors. Not surprising, then that the vultures, tubenoses and some nocturnal birds have larger bulbs than others and therefore are more capable of detecting odors.

Hope your new feeders remain where you place them for a good long time.

I stuck my head in a bag of Niger seed but all I could detect was curry. I'm apparently very susceptible to suggestion and am now feeling quite hungry.

Phil, thank you for allowing us a peek into your birding life during the past year! It's been fun and we are very much looking forward to 2015!

Hannah said...

I tend to think birds mostly detect food by sight, so it was interesting to learn of other senses they use, and the neat feeders for niger seed. I love to see the European Goldfinch, the red on the head and yellow and black wingbars are so lovely!

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