2011 Spring Class #2- Molt

Spring Class #2    5-3-2011

First what shorebirds can be found in spring and fall

Black-bellied Plover Common Common
Am. Golden Plover Rare Fairly Common
Pacific Golden Plover Uncommon Fairly Common
Snowy Plover Local Available Local Available
Greater Yellowlegs Common Common
Lesser Yellowlegs Rare Common
Solitary Sandpiper Rare Uncommon
Willet Very Uncommon local Local, available
Wandering Tattler Uncommon Uncommon Early migrant
Spotted Sandpiper Common Common
Whimbrel Common Common
Long-billed Curlew Very uncommon Uncommon
Hudsonian Godwit Very rare Rare
Marbled Godwit Common Common
Bar-tailed Godwit Very Rare Rare
Ruddy Turnstone Common Uncommon
Black Turnstone Common Common
Surfbird Common Common
Rock Sandpiper Very Uncommon Uncommon
Red Knot Common Uncommon
Sanderling Common Common
Semi-palmated sandpiper Rare Uncommon
Western Sandpiper Common Common
Least Sandpiper Common Common
Baird’s Sandpiper Rare Uncommon
Pectoral Sandpiper Rare Uncommon
Sharp-tailed sandpiper Very rare Very uncommon
Dunlin Common Common
Stilt Sandpiper Very rare Uncommon
Buff-breasted sandpiper N/A Rare
Ruff  Very rare Uncommon
Short-billed sandpiper Common Common
Long-billed Dowicher Fairly common Common
Wilson’s Phalarope Rare Uncommon
Red-necked phalarope Uncommon Fairly common
Red Phalarope Rare Uncommon after storms

In spring in WA there are about 23 common shorebirds, few rare

In Fall in WA there are about 25-26 common to uncommon with about 10 more rare

Tails and Wings  from P 28 in D. Paulson’s first book.

Look that many birds which are Probers tend to copy in appearance Sentinals that they associate with.

Sanderling and Dunlin will fly together, both stripe tailed, bold wing patterns and similar size

Red knot and BBPL both conspicuous wing patterns and white rump, Black-bellied is a sentinel and Red knot a prober.

Note the 5 rock sandpipers can be IDed primarily on their tail patterns, Surfbird and Turnstones band tailed, Tattler plain tailed,  Rock Sandpiper stripe tailed.

Sentinels vs. probers.  See ABA article in 2007 by D. Paulson.

Flocking is social, depends on flight patterns and similar sizes.

Birds in tight coordination flocks need to be very similar in size.

A birds pattern says come fly with me, a social message

Surfbirds, Turnstones, Rock Sandpipers

Dunlin and Sanderlings

Curlews and Godwits

BBPL and Red Knot

Sentinels see the predator first, usually have their head up, give a loud call.  Plovers, Trigines Palaropes, Upland Sandpipers, Curlew

Probers keep their head down, more at risk depend on

Dunlin, Stilts, Dowivhers, Snipes, Peeps.

These are mutually beneficial  Sentinals keep an eye out and have loud calls, probers have large flocks, have softer calls, space less, have heads down.

Convergent evolution:  Curlew & sentinals, Yellowlegs, Phalaropes and Dunlin

In theory probers should increase awareness when alone, and have a higher predation when no sentinels around.


Molt is mostly about the flight feathers, the wing and tail feathers.

Primaries are attached to the hand.

Secondaries attached to the ulna.

In theory to be a true tertial needs to be attached to the Humerus.

Primaries usually #10, numbered from inner to outer.  Usually shed from the inside out.

Secondaries vary in number, numbered from mid-wing inward.  14-38 depending on how  long the wing is in the species.  Usually shed from the outside in and from the inside tertial outward both at the same time.

Tail: Most birds have 12 tail feathers, inside R1 out to R6 on each side.  Usually shed from the inside out with some exceptions (like woodpeckers)

Greater coverts cover the secondaries, primary coverts cover the secondaries.  Median coverts cover the primary coverts.

Scapulars are important in that they are very noticible in standing birds.

Primary coverts usually shed with the primaries they cover.


Modified Humphrey-Parkes Classification System

2003 by Howell.

All You Ever Wanted to Know About Molt

But Were Afraid to Ask

Part II: Finding Order Amid the Chaos

by Steve N. G. Howell

Now all molts are names for the molt that is coming in, i.e. pre molts.  This is from an ABA article Oct

Molting is the regrowth of feathers.  That is all we are concerned about, the growth of a new feather generation, not at all about color, just the growth of the feather.

There are 4 basic strategies:

Simple Basic Strategy SBS  same plumage all year – not many, Albatrosses, some petrals, barn owl.

Wear their juvenile plumage ofor a whole year.  Ne complete molt per year in the fall.

Complex Basic Strategy  CBS   Towhee, Only difference is a formative plumage in the first year.

Simple Alternate Strategy  SAS  One different plumage in the spring, the alternate plumage.  Two molts per year, have a complete fall molt, and a usually incomplete alternate molt in the spring.

Complex Alternate Strategy CAS  Have an additional molt out of juvenile into formative molt, i.e. preformative molt, in the first year, then two a year (3 in the first year)

Birds have one complete molt every year as a general rule, large birds maybe every 2 years.

Other molts are either limited, partial or imcomplete.

What triggers molt?  Length of day, temperature, and suppression of hormonal function activation triggers a molt.

New feathers are in sheeths, and made out of keratin, i.e. pin feathers.

Plumage:  to describe the color of the birds we can use the term aspect.  So in Humphrey Parke we use phrases like adult plumage aspect APA,

Most birds hatched either naked (altrical) or downy (precocial)  The first true feathers are the juvenile feathers, i.e. the B1 feathers.  Most birds in the F1 plumage have an APA.  They retain a few juvenile feathers, so you can sometimes tell they are in formative plumage.

After the birds are adult you say that they have a definitive pre basic and definitive pre alternate molt.  DPB and DPA molt each year.

A few birds have two downy plumages, e.g. flamingos, penguins.  Some have a supplemental molt, i.e. one that is extra and does not fit in.  Possibly Marbled Godwit has an extra very limited molt where the red in the breast becomes brighter as they move north.  Usually after the alternate molt to improve their breeding success.

Some birds have more feathers in the winter than the summer, for warmth.  Big birds have more feathers than small birds.

Birds have to molt.  They cannot survive without molt, so it’s more important than breeding.  More important than migration.  Molt is a high energy cost process.  Most birds do not molt their flight feathers during migration.  Some like dowichers suspend molt during migration and resume at staging areas enroute.

Dark feathers wear the slowest, light feathers the fastest
Small birds generally separate molt from breeding.  Larger birds can molt during breeding, but not while laying eggs. Female hawks may start molt prior to laying eggs, suspend this to lay eggs, and then finish after eggs are hatched.  Males are smaller so wait to start until after the birds are off the nest and still finish on time because they are smaller.

Timing of molt may depend on the length of migration, others go to a staging location enroute on migration.  May depend on food supplies, other factors.

IN 1983 no body knew where black swifts winters, but they had never been seen molting in NA, and so we knew they had to winter in South America.  So by looking there they were found in S. America. Opposite with Cave Swallows, known to be in molt in NA, and finally found wintering in Mexico.

Molt sequence:  Flight feathers first P1à P6, then secondary molt starts both ways from the middle on out.

Color of feathers can change based on when the bird is born and when they molt.  Male House finches, CBS, if they molt Augà Oct in first year can be red, if molt in Julyà Nov can be partially red or yellow. If they molt after Nov they can be female aspect.  (pre Howell in Molt book)

Types of molt:

Complete all feathers

Incomplete:  all except but some flight featehrs

Partial:  Most body but no flight feathers

Limited: Some of the body but not all.

Molt Contrast:  Some of the coverts, some scapulars may be adult like and others juvenile like.  This contrast between new and old feathers is called molt contrast.  Can help with aging some species.

4 types of wing molt:

Standard sequential  P1àP10, Secondaries start about when P6 is molting, starting from the outside in and inside out.  Meet in the middle.   Eccentric sequential is a variant of this.

Synchronous wing molt:  simultaneous dropping of the wing feathers.  Typical of larger birds.  No flight.  Loons, greges, murres, waterfowl, puffins.  Dippers shed P1-6 synchrounously, then P7-10 seqentially.

Stepwise:  Old term is Stauffelmauser.  Long winged birds that weigh over 1 Kg.  Starts where the last molt left off and at P1.    Think of Golden Eagles.  Molt about from P1 à P6 or P7.  Second molt goes P1 and P7 or 8.  In third year may start at P1 P4 and P8.  Osprey has an accelerated stepwise molt.  Some are obligate.  Because of their size they have to do this.  Others are opportunistic stepwise molters, especially female large buteos.

Factors affecting molt.  Birds locked in by their genetic ancestry.  Food can affect molt.  Body size affects molt.  Migration strategy affects molt.  Most resident and short distance birds tend to be CBS.  Most long distance migrants tend to have an alternate strategy.  Habitat is important.  Birds deep in the forest tend to be CBS.  Woodpeckers, thrushes etc.  Edge birds tend to be CAS, in the sun more.

Birds that have the least amount of time not migrating molts the least, longer migrating molt the most.


3 types: 

Pigmented Carotinoids and melanins. Melanins black, brown and rusty.  Synthesized by the bird directly. Provide strength.  Carotinoids provide bright colors, from the diet, needs to eat something in the diet and synthesize it, reds pinks, oranges, yellows.

Structural Blue and white, produced by interference with light rays.  Fine structures in the feather bend the light to produce the color.  Blue absorbs everything but the blue and reflects the blue.  Like Stellar’s jays, indigo buntings.  Keratin scatters light.  No pigment scatters light.  Irridescence varies with viewpoint and is due to fine structures in the feathers.  Fine structures on the gorget in Hummingbirds reflect the light.  This changes with the angle of view.  Cosmetic is the staining of feathers by the bird.  Like Sandhill Crane puts mud on the feathers.  Reddish blush on the gulls is dietary.  Staining on swans and geese is feeding in rust deposited water.  It is incidental.  Not intentionally applied, so not cosmetic.