Oh No, Bills Again?


Some years ago now, excellent birder and bird photographer Richard Ditch and WC co-authored a couple of articles on bird identification for bird photographers. Richard did most of the work, and made an excellent point: a bird’s bill is a good starting point for identifying the bird’s species and figuring out how the bird makes a living. With that credit to Rich, WC will undertake to give some examples of the astonishing evolutionary adaptations of birds’ bills to birds’ business.

WC bets you thought we were done with bills. Heh. After 65 million years of evolution, we’re barely started. We’ve done shredders, pollinators and spears. Today we’ll have a look at probers.

An amazing number of species have evolved bills designed to probe, sometimes probe a long ways, into mud, dirt, wood and other stuff in the quest to get a meal. Shorebirds are an obvious example.

Long-billed Curlew, Malheur NWR, 2017

Long-billed Curlew, Malheur NWR, 2017

The Long-billed Curlew is North America’s largest shorebird and boasts the longest bill, as well. As you’d expect, off its breeding territories, the curlew probes deeper. Oddly, on breeding territory they are mostly surface feeders. In Idaho grasslands, grasshoppers make up the bulk of their prey.

Whimbrel, Pucusana, Peru, 2016

Whimbrel, Pucusana, Peru, 2016

The Whimbrel is another very long-billed shorebird and a cousin to the Long-billed Curlew. They breed in Alaska; WC has photographed them at 4,000 feet on the south slope of the Alaska Range. They winter in South America, a pretty impressive migration route. This fellow was raiding mussels and barnacles along a rocky shoreline at 12°25′ South. The stouter bill of the Whimbrel is adapted to deal with the molluscs and crustaceans, but like the curlew, the bill can snag bugs in Alaska.

Long-billed Dowitcher, Peat Ponds, Fairbanks, Alaska

Long-billed Dowitcher, Peat Ponds, Fairbanks, Alaska

The Long-billed Dowitcher, by comparison, is an extremely enthusiastic prober, so much so that it looks like some kind of sewing machine, repeatedly probing to the hilt of its bill. Watching it forage, you wonder how it breathes. This particular bird stopped only because it was out on lake ice.

Wilson's Snipe, Long Valley, Idaho 2016

Wilson’s Snipe, Long Valley, Idaho 2016

A smaller, but equally impressively-billed bird is the Wilson’s Snipe. You can see the very stout bill, and that the eyes are set far back on the head. The snipe actually has binocular vision behind itself, allowing it to see when it is probing for food. Wilson’s Snipe might be the deepest-probing shorebird; it often probes with its head submerged to its eyes.

Any discussion of birds with probing bills would be incomplete without talking about sandpipers.

Western Sandpiper, Hartney Bay, Alaska 2012

Western Sandpiper, Hartney Bay, Alaska 2012

Sandpipers have shorter bills than the other birds described in this post, although they are still impressively long in relation to the birds’ size. As this photo shows, they probe for food. But sandpipers do something else interesting with their bills: they function as a “straw,” allowing to the bird to sip up biofilm – you and WC would call it pond scum. It turns out that biofilm is highly nutritious. Sandpiper bills are compromise between probes and straws.

WC doesn’t want to give the impression that long probing bills are only found on shorebirds.

Red-billed Scythebill, Pantanal, Brazil 2014

Red-billed Scythebill, Pantanal, Brazil 2014

A scythebill is a species of woodcreeper.

Red-billed Scythebill, Pantanal, Brazil 2014

Red-billed Scythebill, Pantanal, Brazil 2014

You can see how the species got its name. And that long, probing bills are not limited to shorebirds.

WC could go on at length (sorry) on the incredible diversity of probing bills. A shorebird specialist would complain WC has barely touched on the subject. But there are lots of other bird bill strategies to touch on.

 

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