Why Jackdaws can cause havoc in a chimney

Well, it may disappoint the RSPB, but Jackdaws most certainly are not a sweep’s best friend, nor are they particularly the friends of the people whose chimneys they build nests in.


Normally you would assume that any bird rash enough to build a nest in a working chimney would soon expire from monoxide poisoning, but Jackdaws do seem bullet proof.  I have taken a nest full of chicks out of a chimney.  The householder’s family had nearly died from monoxide poisoning due to the chimney being blocked, but the chicks were fat and in excellent health.


Jackdaws like chimneys, and if you have a nest in your chimney, it is a given that it will have been built by a jackdaw.  No other bird has quite such a love affair with our flues.


While they seldom are found in modern, post 1965 chimneys (though you will find a few) their favourite flues are the Victorian constructions.  These tend to have rough internal surfaces, and corners to aid in keeping the nests up there.  While such bends are easy to build in, and the horizontal surfaces of the big inglenooks are also easy, most of the nests are situated in comparatively straight flues.  Their trick to making this work is also the item that makes them so hard to shift.


The main constructional material of the nest are springy twigs that are flexible enough to bend well.  The jackdaw takes hold of the twig in the middle and proceeds to work its way down the flue until it feels adequate resistance from the twig being pushed down.  If the lining is too smooth, the bird wil keep pushing down until the twig falls out the bottom.  It will repeat this for a number of times, until giving up on the chimney as a bad deal.


As soon as a twig lodges, off goes the bird for another one which is pushed down until it lodges against the first, then another, and another until a dense mat of ‘U’ shaped twigs has  been built up.   This is the foundation on which the rest of the nest is constructed, and it is this foundation that is such a problem to the sweep.  The U of each twig won’t easily move when struck by the brush, and the brush itself can’t penetrate.


The usual technique is to put a battering ram on the end of the rods and give the nest hell.  The game is to loosen the mass of the nest by passing the ram through it repeatedly until the core starts to break up and fall down the flue.  Eventually enough falls to allow the brush through, and with that the sweep is able to dislodge and remove the twigs that are left.


Once the nest is removed, it is VITAL to get a properly designed birdguard onto the pot the same day.  Leave it 24 hours and the birds will have started to rebuild it.  Within a very short period, (sometimes just 24 hours,) there can be enough new material in the flue to block it off a second time.  The best advice is, have someone standing by to fit the birdguard the minute the sweep hascleared the flue.

This entry was posted in Blog Articles. Bookmark the permalink.

Comments are closed.

  • Are you thinking of installing a stove?
    Ask the specialists
  • Site Survey
    Please fill in your details below and a member of our team will be in touch shortly to arrange a visit

    Or alternatively, contact us by telephone or email on:
    01223 964803
  • Testimonials

    The Chimney Corner provides a swift, thorough and professional job!Ms LucchettaCambridge
    I would not hesitate in recommending The Chimney Corner as highly professional experts in the assessment and maintenance of chimneys. The technician took great care to ensure the house remained clean, to point out some serious problems and discuss possible solutions. He gave me clear indications of unexpected costs before embarking on any work and even advised me where he considered work might be unnecessary.Mr SharpWorlington
    Many thanks for your extreme efficiency! Makes our life a lot easier!Redmayne Arnold & Harris
    Chimney survey was great and the only way to really find out for sure what was happening.Mr and Mrs WilamowskiAbbotsley
    We have always been impressed with the high standard of work carried out at competitive prices and the helpful, congenial attitude of the staff. We will continue to employ their services and have no hesitation in recommending their work.Bidwells Residential Lettings
    We have used this company for the last 15 years and have always been pleased with the polite and efficient service. Care is taken to ensure that the property is left in a clean condition and a full report is provided once the work has been completed. We would definitely recommend their services.Inter-let Property Management