Biological Seed Dispersal Agents

Thursday, December 15, 2011 Adam Tilt 4 Comments


Biological seed dispersal agents, or Jackdaws as I prefer to call ours, turned late morning lie-ins into a distant memory for us this past autumn. Where once upon a time we took for granted the peace and quiet of our semi-rural location we now found ourselves under attack from a barrage of hammering. To make matters worse this wasn't any eager beaver DIY enthusiast at the other end of the street either but instead something that sounded a bit like a pneumatic drill on our very own roof. At first we were a bit baffled as to who or what the culprits could be until we started stepping on these all over our garden paths.

25242 - Biological Seed Dispersal

You may think that finding an acorn is not that unusual but we were quite surprised considering that our nearest Oak tree is a good distance away from the house. Closer inspection revealed that most of the acorns had been pecked at by a large beaked bird, and with no visiting Jays our suspicions immediately fell on the ever hungry Jackdaws. Eventually we caught one red handed (footed?) as it arrived with an acorn and proceeded to use our roof as a rather expansive nut cracker.

Despite the disturbance it was great to see one of natures processes in action. Oak trees, like many other plants, rely on birds and animals to carry their seeds away to a location that will hopefully be suitable for germination whilst providing no direct competition to the parent. The most common 'biological dispersal agents' of acorns in this country are Squirrels and Jays, both of which bury huge numbers each year to provide them with a food supply during the cold winter months. Even though Jays in particular have an incredibly high retrieval rate there is always a certain percentage that will remain undiscovered of which a few will eventually grow into new trees. Through this method a single tree can bring new growth to areas many kilometres away from its location, and that's exactly what has happened in our front garden.

25240 - Biological Seed Dispersal

The young sapling above burst out of the soil this year but I imagine the acorn that generated it was probably dropped the previous autumn. It has grown an impressive amount during the intervening months but unfortunately the patch of soil it calls home is right next to the house. As much as I would like an Oak tree to look out at I don't think the buildings foundations would welcome the roots as they start to spread. Instead I shall be transplanting it to the back garden where it can join what I am hoping will eventually turn into a small wooded area.

4 comments:

  1. we've had the same occurence here - with blackbirds and grackles swarming into the oaks and dropping acorns and pieces everywhere - on the house, porch and yard. :)

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  2. Some of our feathered friends do make good gardeners lol

    Hope the sapling transplants successfully Adam.

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  3. A wonderful post Adam.. I enjoy watching the Jays burying acorns.. I just can't manage a decent image though...
    I have asked Santa for a small bird hide...

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  4. TexWisGirl - it saves planting new trees I suppose!

    Keith - and me. I'll let you know how it goes next year.

    Andrew - Jays are such hard birds to get a decent photograph of. I had a bit of luck last year but that's it.

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