Flora Day attracts thousands to the Cornish town of Helston every May.
But the event coincides with swans nesting at Coronation Lake, which can be "very disturbing" for the birds, Heston Town Council said.
Last year a swan laid eggs on the edge of the road, leading to an area being fenced off. Photographer Rebecca Wilbur floated the idea of hiring security to protect them during the event.
The council has backed the plan and a social media campaign has raised £310 to cover the cost of employing guards to protect swans and their eggs.
More on this story, plus other Devon and Cornwall news
Councillor Dave Potter said: "When it gets very busy, it's very disturbing for the swans at that very critical time of their cycle."
Mute swans nest in April and May. Flora Day normally takes place on 8 May.
It involves couples dancing through the streets and in and out of homes and shops to "drive out the winter and welcome spring".

RMT general secretary Mick Cash said it was "shocking" to have "sprung this announcement once all the Christmas deliveries have been completed".
Employees and sub-contractors working for the firm have been sharing their stories and reactions.
Stefan Thorrington in Exeter, Devon
I have five vans in City Link colours and five drivers who have all been working flat-out up until Christmas Eve to make sure everything was delivered.
We didn't have any warning about this whatsoever - drivers even knew which routes they were going to cover on Saturday.
Last night I was pondering what to do. None of the managers at the depot knew about this - they were under a lot of pressure to deliver everything by Wednesday.
However, I do think someone must have known what was going on.
I don't know what's going to happen now. The main question is do I get paid?
Paul Horner, Kirkcaldy
I'm a sub-contractor at a local City Link depot in Fife and have been there for three years. I'm totally and utterly gutted.
This has happened after they spent money on new uniforms and new scanners.
Everyone thought we had turned a corner and things would be getting a lot better, but obviously not.
I found out on Christmas Day. I'm still pretty numb. I've just told my fiancÃ©e (I couldn't bring myself to tell her yesterday). She's distraught.
I just hope I get paid at the end of the month because, like all the other sub-contractors, I need money to live on, to pay for the van and the diesel.
Irfan Khan, Beckton, London
We have 20 drivers and a fleet of vans that need paying up. We have probably lost Â£70,000 in unpaid invoices.
We haven't got the capital to pay it so we'll probably sell the vans, and the drivers probably won't get paid.
We just don't know what's going to happen.
We've worked until midnight nearly every day last week up to Christmas.
I have not slept since finding out, I've been going crazy.
Geoffrey Goddard, Teddington
I work for City Link as an infrastructure engineer in the Heathrow office, I have been employed as a permanent employee for six months now.
I almost half expected it but we hoped we could turn the company around.
I could see a few faults. There were lots of layers of management, there were basics which needed doing and no engineers on the ground.
They weren't getting the fundamentals right.
Simon Judd, Essex
I'm a sub-contractor with City Link, now find I have a liveried van and no work.
I doubt if I'll get paid for my last two weeks' work, nearly Â£2,000.
They've got rid of most employed drivers at my depot, and presumably nationwide. Just have to hope I can find some work elsewhere, after getting the van made white!
I worked for the company for eight or nine years but recently became a self-employed driver for them.
Most drivers at this depot are self-employed, so I don't know about the figure of 2,727 people, it depends how they're counted.
Bodyguards are to be hired to protect nesting swans at an annual gala.
[NEXT_CONCEPT]
Parcel delivery firm City Link announced on Christmas Day that it was going into administration.