Because my home-made dish feeders were not very satisfactory in wet weather, trials were, so far as possible, conducted in dry weather. The dish feeders were replaced in wet weather by my tube feeders [see below] filled with commercial mixed grain to maintain the birds' feeding habits at the trial location.
In each trial I positioned the 4 dish feeders holding single seed types [‘singles’] as follows:
At approximately hourly intervals I rotated the support clockwise 90° to eliminate feeding preference determined by location rather than food type.
|TRIAL 1||EACH FEEDER STARTS WITH 4 OZ OF SEED||REMAINING*|
|3||BLACK SUNFLOWER||2¾ oz|
|4||MIXED SMALL SEEDS***||2¼ oz|
* Remaining at c. 4 p.m. Dishes were filled fresh each day at about 09:00
** The peanuts were slightly crushed, not whole.
***The ‘mixed small seeds’ used in Trial 1 seemed to consist of red and yellow millet, rape and maybe others. Single small seed trials awaited supplies of each seed type.
Following Trial 1 I decided not to rotate the feeders on an hourly basis! To do so was potentially confusing both to birds and the experimenter. So the feeders were positioned as shown at left and tethered when necessary to prevent rotation by the wind. I intended doing separate trials later using preferred single seed types in different positions to eliminate the possibility that an apparent preference for a seed variety was in fact a preference for a particular position. [See notes after Trial 2]
Trial 1 was something of a teething run. The clearance gap at the bottom of the holding tubes proved inadequate to allow free flow of peanuts and sunflower seeds. I modified the feeders slightly to remedy the fault.
|TRIAL 2||EACH FEEDER STARTS WITH 4 OZ OF SEED||REMAINING|
I left the 2 tube feeders filled with ordinary mixed seed in situ for Trial 2 as shown in the image above. To my surprise, these seemed to attract as much interest as the dish feeders containing singles. Finches [‘Gold’ and ‘Green’] in particular were drawn to the tube feeders and shovelled out great quantities of seed in search of something. They either enjoy shovelling on the same principle as General Peckem [or was it Major Major?]; “while none of the work we do is very important, it is important that we do a great deal of it”] or they were looking for something other than peanuts, black sunflower, maize or hemp, each of which was to be had more easily and in greater quantities only inches away. [I later found that Greenfinches had a liking inter alia for hemp and niger.]
Trial 3 was an attempt to eliminate the possibility that birds' feeding was determined by preference for the feeder location rather than its contents. Trial 2 was therefore repeated but with the positions of the preferred seed being swapped with that least favoured, and the middle two being reversed.
|TRIAL 3||EACH FEEDER STARTS WITH 4 OZ OF SEED||REMAINING|
I concluded that Trial 3 showed that birds' preferences were based on seed type rather than the location or orientation of the feeder.
|TRIAL 4||EACH FEEDER STARTS WITH 4 OZ OF SEED||REMAINING|
I re-ran this trial in dry weather. There was a shower early on and the Niger seed got damp, which may have accounted for its apparent lack of appeal, before the day turned fine. I saw birds land on the Niger dish - Blue Tits and Greenfinch - so it did not go unnoticed. For those who don't know, Niger seed is very small, fine and easily blown. It is rich in oil.
|TRIAL 5||EACH FEEDER STARTS WITH 4 OZ OF SEED||REMAINING|
* VARIATION In order to get a slightly better idea of how much seed might be consumed if freely available, the feeders were topped up as they became empty. Hence some of the figures for consumption exceed the 4 oz amounts used in previous trials.
Blue tits and Greenfinches were seen landing on the Niger dish, then leaving without feeding. Most flew to the Peanuts, which in Trial 5 had been positioned where the Niger was in this trial. I only noticed one Greenfinch that appeared to feed briefly from the Niger - but then I had other things to do! Goldfinches continued to feed from the tube feeders and ignored all the dish feeders including that with the Niger seed. In the image at left, the Niger feeder is the one without birds on. As well as the two Goldfinches shown on the tube feeder, when the image was taken another Goldfinch was on the other tube feeder just out of shot to the right. The Greenfinch in the image is on the Sunflower feeder. [I later found that Goldfinches have a particular liking for niger seed.]
The birds could possibly have eaten more than 12 oz of Peanuts had I been able to keep the feeder stocked all the time but I found it empty on three occasions; how long it had been empty I don't know. Of course birds can easily make off with a greater weight of Peanuts compared to any of the other trial seeds.
To replenish the 2 tube feeders each day required approximately 1½ lbs of seed. That did not mean the birds actually ate that amount, because they did not. Birds, like Onan, cast their seed upon the ground. See previous images, pages etc. But I was surprised by the continued enthusiasm the birds showed either for the mixed seed or the tube feeders. Was the high visibility of the mixed seed in the tube feeders a stronger stimulus than the single seeds visible in the dishes? The seed in the tube feeders was visible from 360° whereas that in the dishes was only visible from above the horizontal plane of the dishes. Next trial used mixed seed in dish feeders and single seed in the tubes. “That'll fox them!” I thought.
VARIATION. Mixed seed was placed in the 4 dish feeders, un-mixed Black Sunflower [at A] and Niger [at B] in the 2 tube feeders. [See image at top of page.] A was to the NW and B to the SE but when filled with mixed seed birds showed no preference for one position over the other i.e. previously they have both emptied at the same rate. “Consumed” represents the total amount used during the course of the trial i.e. ca. 12 hours but did not necessarily mean eaten.
During the course of this trial I had opportunity to note what birds fed on what grain and from which source as shown below. [Table modified by addition of HEMP - see under Trial 8 on 3 March 2011]
✔ Frequent feeder.
✦ Occasionally seen on feeder but not seen eating.
I also noticed the following. Several species [see table above] landed on the Niger but were not seen to eat any. Chaffinches and Sparrows landed on the Niger feeder only rarely, whereas Greenfinches, Great and Blue Tits inspected the Niger briefly before usually flying straight to the Sunflower where they fed. Greenfinches occasionally ‘sipped’ at the Niger. For Goldfinches the reverse was true. They occasionally landed on the Sunflower but invariably left without feeding and only fed on the Niger. While on the Niger Goldfinches did not ‘shovel’ as they had when the same feeders contained mixed seed. At no time were Goldfinches seen on the dish feeders containing mixed seed. This indicated that Goldfinches either do not recognise the dish feeders as sources of food or distrust them. In this trial the dish feeders contained the same food that they so assiduously shovelled from the tube feeders in the previous trial, and in the previous trial a dish feeder containing straight Niger seed, which they did not touch while it was in the dish feeder, was the only thing they ate when in a tube feeder. Goldfinches in my garden appeared to eat only Niger but no other birds seemed interested at the time. I have never seen Siskin or Redpoll here in Somerset - two other birds often cited as eating Niger. As these were seed trials, birds which do not eat any of the above seeds but which eat peanuts e.g. Great Spotted Woodpeckers and Long-tailed Tits Aegithalos caudatus were not recorded.
If Goldfinches were looking for Niger in the mixed seed in the tube feeders, their shovelling is hardly to be wondered at. The mixed seed, ‘Bestpets Premium Wild’, [NOT an endorsement; it is as poor as all the others I have tried!] contains Niger in infinitesimally minuscule quantities. In a random 4 oz sample there was too little to weigh accurately but amounted to less than half a teaspoonful and was equivalent in weight to approximately 2 peanuts! Compared to the pure Niger seed sample I had, the Niger contained in the Bestpets mixed seed appears of very poor quality - very small and shriveled. It may be enough to satisfy the legal requirements for stating that the product contains Niger but not enough to satisfy this customer - nor the ones in my garden!
To the seeds and feeders in the previous trial I added a tube feeder with HEMP SEED and noted on the previous table which birds were attracted to it and which ate it.
My promised supply of other single seeds failed to materialized [“Ring back in a week…” etc. etc.] Until it did I continued feeding as above i.e. 4 dish feeders with mixed seed, 3 tube feeders containing single grains of black sunflower, niger and hemp and 1 peanut feeder. Don't want the birds getting peckish.
I noticed a Goldfinch on one of the dish feeders for the first time today. Obviously unadventurous, slow learners! They also fed from the ground below the niger feeder, so feeding on the ground per se not inimical to them, but they seem disinclined to forage or experiment. Thoroughly conservative, they seem to “know what they like and like what they know.” But they are pretty.
Once my stocks of seeds ran out I decided to pander to the birds' preferences and have fed only whole black sunflower seeds and peanuts with the occasional exotic thrown in as well as fat balls. I have completely stopped using mixed seeds. I continue [in 2018] to get the same variety of birds as in 2011.
© 2018 Duncan Linklater