Google Search Q&A 6

Spuggies! (By Daniel Marchese on Flickr, CC-BY-2.0)

It’s been a long time since we did this, and the boring reason why is that Google now encrypts its search engine referrals (officially for privacy reasons, but it will still show you search terms for paid search adverts…)

But not every search engine does, and the “Search terms” box in our stats page has been very slowly filling up…

  • dove mixed with sparrow
  • pattern of sparrow for embroidery
  • sparrow in cross sticking
  • difference between mocking jay and sparrow
  • small brown garden bird
  • small speckaled uk sparrow like bird
  • what would the difference be when reffering a person as a dove rather than a sparrow
  • cayenne pepper and sparrows

…with sparrows.

Today, we’re going to answer one (non)Google Search with the help of another.

  • nom of sparrow graph
  • sparrow energy drink

Given that sparrows are some of the most abundant birds in Europe, you’d think it would be easy to find out what they eat, but… well, there are two ways to study that. The first is to watch them for days and days, carefully noting everything they eat, and the second is to peer at the mush in their stomachs. Neither is especially appealing, so it looks like the only scientific study that has been done on house sparrows was over 100 years ago (1910-12), which involved not only cutting up sparrows, but carefully collecting their droppings and planting them in sterile soil to see what sprouts (answer – weeds). As such, let’s all take a moment to salute the work of Walter Collinge, author of The food of some British wild birds: a study in economic ornithology. It’s all free online, if you’re ever dying to know what’s in a bird’s guts. There’s also some data on what tree sparrows eat thanks to Anton Krištín, a Slovakian scientist who spent his time studying tree sparrow vomit. The paper (mostly in German, although the summary is in English) is also available for free – I recommend looking at Figure 5 (even if you don’t speak German) as a clever way of getting a point across in a graph.

The data I’m using is a slightly cleaned up version from “A review of invertebrates and seed-bearing plants as food for farmland birds in Europe” by JM Holland et al. The problem with Collinge’s data is that he was more interested in the effect birds had on farms than their dietary requirements, so he just counted the number of things each bird ate. This is not great when you’re trying to compare individual grains of wheat or aphids to whole caterpillars. Holland et al have turned it into a percentage, but they warn that it’s still not directly comparable with the data on other birds. So if you’re ever in a life-and-death situation where you really need to know what a house sparrow’s diet is proportional to a tree sparrow’s, then… don’t use this.

So, here are your graphs of sparrow nom!

Diet of a house sparrow in breeding season (% occurrence)

Diet of a tree sparrow in breeding season

Diet of a tree sparrow outside breeding season

Of course, sparrows are notorious opportunists, and they’ll eat whatever they find. Here’s some of Collinge’s data about what he found in sparrows in fruit-growing districts, agricultural districts and suburbs respectively:

House sparrow diets by location (% occurrence)

 That graph doesn’t include bread, but that was also a big part of sparrow diets (annoyingly, he doesn’t give the amount, but 86% of suburban sparrows had some bread in them).

So, there’s sparrow noms. Now for the second part… sparrow energy drinks!

A house sparrow needs about 25 dietary calories a day (calculated from Figure 10-4 in Avian Physiology), which is about 1% of what a human needs… but weight-for-weight, they need nearly 20 times as much energy as we do (flying isn’t easy, and those poor little sparrow hearts are going at nearly 500 BPM). So they’re the ideal market for energy drinks (apart from the whole “no ability to even mentally contain the concept of money, never mind participate in the global economic system” thing).

So, what can we give the sparrow that’ll fulfil its needs? Wheat contains about 3.1 calories per gram, sunflower seeds contain about 6 calories per gram, and crickets have 1.2 calories per gram, and that’s probably a good spread of nutrients too. So 2 grams of sunflower seeds, 2 grams of wheat, and a bit of cricket, in a blender… that’ll keep a sparrow going until lunch!

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