Albino and partial albino birds The presence of white feathers on a normally dark bird is the most frequently seen color abnormality. Every birder can expect to encounter white or partly-white birds with some regularity, and the more striking examples will stand out even to novices. All black and brown coloration in birds comes from […]
Abnormal coloration in birds: Melanin reduction Read More »
This is a follow-up to my recent post about Optical illusions and bird identification. While working on some heron studies the other day, I found a good example of an illusory bill size comparison. Compare the bill in the two images of Reddish Egret shown below. To my eye, at least, the bird on the
More on illusions of size Read More »
In a footnote here I mentioned that blackish feathers can appear gray because of powder down, and now I will offer a little more explanation.
Powder down and the Black-crowned Night-Heron Read More »
Here is a classic optical illusion – the three horizontal lines in the image below are all the same length. Yes, they are identical (move your cursor over the image to see the proof). I’ve been pondering this illusion and wondering how often we see similar effects in bird identification. I suspect that a lot
Optical illusions and bird identification Read More »
A Korean translation of this post is here With the recent surge in the availability of digital audio devices, the use of playback to attract birds into view has increased exponentially. This has fueled an ongoing debate among birders about the ethical issues surrounding the use of recorded bird songs in the field. There is
The Proper Use of Playback in Birding Read More »
Phenology is the study of the timing of natural events, and I have recently begun to realize how useful it is for distinguishing subspecies of birds. In San Diego in Mar 2009 I noticed differences in behavior and molt timing that were helpful in distinguishing Belding’s and Northern Savannah Sparrows. I wrote about this again
Subspecies by phenology – Great Blue Heron Read More »
In a recent post on his excellent blog Earbirding, Nathan Pieplow points out an issue with the voice description of Buff-collared Nightjar in the Sibley Guide to Birds, which says: Song of rapid, sharp, dry chips in crescendoing series tup to to tu tu ti ti trridip accelerating and rising to flourish at end; pattern similar to
Kingbirds, nightjars, and the perception of bird sounds Read More »
On October 9th, 2005 I was enjoying the view at First Encounter Beach in Eastham, Massachusetts and watching a small flight of seabirds. A flock of gulls began to gather on the beach close to my car and I found myself more and more engrossed in the plumage variation of Ring-billed Gulls. This first photo
Variation in immature Ring-billed Gulls Read More »
Determining the age of a goose can be helpful for identification, and can also reveal some interesting behavioral and ecological information by enabling you to sort out family groups and subflocks. Given good views it’s not hard to distinguish Canada Geese that are still in juvenal plumage from those that are in adult plumage. By
Ageing Canada Geese Read More »
One of my regular birding spots is a small farm field near my house in Concord, Massachusetts. I can walk around the entire place in about 20 minutes, but I usually take about two hours and get in some good sparrow-study. The clump of taller vegetation shown here is always a good spot to study
Probability in bird identification Read More »