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Seed Preferences

Time: 2 Class periods Setting: Schoolyard Type of Organism: Plants mammals Habitat: All
Biodiversity
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Guiding Questions

Do seed eaters have preferences for specific kinds of seeds? What factors determine preferences for different seed types? Do preferences change in different habitats or micro-environments?
    Overview

    Seed eaters, like the white-footed mouse, must be able to find, collect, process and then store or eat enough food for their immediate and year-long needs. While doing so, they must avoid being eaten themselves and must not expend too much energy in the processes of searching for and handling the seeds. This study lets you explore some of the fascinating adaptations small seed eaters have for finding, choosing, and handling seeds in the schoolyard.

    You will be embedding seeds into soft beeswax so that the teeth marks of the seed eaters can be seen and hopefully identified. These will be placed out as seed caches and the number of seeds removed measured in one weeks time. There are a number of factors you could consider in your study:

    • seed type, e.g., compare preference for sunflower versus maple seeds.
    • seed coat, e.g., compare removal of intact seeds versus those with the seed coat removed.
    • seed number, e.g., see if caches with many seeds are more attractive than those with few seeds.
    • micro-habitat, e.g., compare seed disappearance from caches in small versus large openings in the meadow.
    Materials
    • sunflower, bean, sugar maple and Ailanthus seeds
    • petri dishes or wood pieces for at least 10 seed caches per group
    • beeswax
    • flagged stakes for marking caches
    • permanent marker for marking flagging for record keeping
    • grass clippers (optional)
    • rubber gloves for handling caches at the end of the study

    Decide on what comparison you want to make, and then prepare your caches and the sites you will place them in.

    1. Decide on what type(s) of seed you will use. If you are comparing seeds with and without seed coats, prepare adequate numbers of each type. Consider issues such as seed size in your thinking. You'll almost certainly want to include more than one seed of each type in each cache.  
    2. Embed the seeds into the beeswax, leaving approximately half of the seed exposed. Prepare all replicate caches in the same fashion. Number each cache, and keep precise records of the numbers and types of seeds in each.  
    3. Number the flagged stakes and then use them to mark the locations for the caches. If you are NOT comparing different micro-habitats, then try to select locations that are as similar as possible. If you ARE comparing micro-habitats, etc., then try to make sure that your replicates within each site are as similar as possible.  
    4. If you are comparing small versus large openings in the meadow, then use the grass clippers to create openings of the appropriate size.<  
    5. Carefully place the caches adjacent to the stakes.  

    Collecting data about seed preferences

    CAUTION: Many of the small mammals in our area can be vectors of disease. DO NOT touch feces or surfaces with urine; use rubber gloves.
     

    1. Carefully examine each cache in situ (i.e., at the site) and record any evidence of animal activity.
    2. Retrieve each cache and take them to a place where they can be examined carefully.
    3. Record the fate of each seed - in tact, partially eaten/removed, totally eaten/removed - and the evidence of teeth marks for each.
    4. Summarize your results:
      • Percentage of each seed removed under each treatment.
      • Frequency of evidence of mice and other seed eaters.