SFBBO Gull Workshop 1 Alvaro Jaramillo

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SFBBO Gull Workshop 1Alvaro Jaramillo
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Why I like gulls? Not sure, but they make me go
wow!
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I just think they are pretty!
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I just think they are pretty!But I also like the
element of the unexpected
Chris Gibbins
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My Aims

• Teach you the basics of gull ID.
• Get acquainted with the details of gull ID.
• Take the fear out and put the fun in!
• Gull biology - put our gulls in context.

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The Plan

• Today
• Introduce the adult gulls
• identification concepts.
• Taxonomy, life history, conservation
• Ageing

• Thursday
• Refresh
• Molt
• More on Ageing
• Young gull plumages
• Identification challenges
• Rare Gulls
• Gull behavior

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What are Gulls?

• Charadriiformes
• Related to shorebirds, Alcids, Terns, Skimmers,
  Skuas etc.
• Sister group to the Terns.
• Webbed feet. Strong bills. Long wings, short
  tails.

The Inca Tern of the Humboldt Current is a rather
gull-like tern!
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White-headed Gull species Larus

• Western
• Glaucous-winged
• California
• Herring
• Thayers
• Glaucous
• Ring-billed
• Mew
• Heermanns

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Hooded Species - Leucophaeus

• Franklins Gull
• Laughing Gull
• Others in Latin America

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Masked Species - Chroicocephalus

• Bonapartes
• Black-headed
• Others in Asia, Europe, South America, Africa.

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Arctic Gulls, Kittiwakes, etc.

• Sabines Gull and Ivory Gull (Xema and Pagophila)
• Kittiwakes (Rissa)
• Little Gull (and Rosss) Hydrocoleus

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The regular gullsin extremely rough order of
abundance
Green Winter only

• California
• Western
• Glaucous-winged
• Ring-billed
• Herring
• Mew

• Heermanns
• Bonapartes
• Thayers
• Glaucous

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Uncommon, Rare, and ultra-rare!more details next
class.

• The regular ones
• Black-legged Kittiwake
• Franklins Gull
• Sabines Gull

• The rare ones
• Slaty-backed Gull
• Vega Gull
• Little Gull
• Lesser Black-backed Gull
• Iceland Gull
• Black-headed Gull
• Laughing Gull

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Why are gulls so difficult?

• Complex aging
• Variable
• Wearing and bleaching
• Constantly changing (molt)
• Hybrids

For some this is what makes them fun!
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Ring-billed Gull - Adult
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Ring-billed Gull 2nd year
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Ring-billed Gull 1st Year
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Variability
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Wearing and Bleaching
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Constantly changing - molt
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HybridsBeware these are common in winter.
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Parts of the Gull - Flight
Learn your chicken bone!
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The chicken bone again!
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..and again!
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Parts of the gull standing and flying
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Gull Lingo Mirrors, Tongues and Trailing
Edge
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Gull Lingo Gonys, Gonydeal Angle and
Orbital Ring
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What you look at?

• Shape size (bulgy bill, long wings, slim, fat,
  thick-necked, bulky)
• Mantle color (relative)
• Primaries
• Leg color
• Eye color
• Streaking pattern

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Impression
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Other Issues

• Lighting
• Uncertainty you just never know. And that is
  fine!

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Lighting overcast better than sun.
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What the ???
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Identification Intro adult White-headed Gulls.

• California
• Ring-billed
• Mew
• Western
• Glaucous-winged
• Herring
• Thayers
• Glaucous
• Heermanns

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California Gull - Adult
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California Gull - Adult
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California Gull - Adult
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Ring-billed Gull - Adult
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Ring-billed Gull - Adult
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Mew Gull - Adult
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Mew Gull - Adult
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Ring-billed vs. Mew Gull
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Western Gull - Adult
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Western Gull - Adult
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Western Gull - Adult
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Glaucous-winged Gull Adult
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Glaucous-winged Gull - Adult
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Glaucous-winged Gull - Adult
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Glaucous-winged Gull - Adult
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Herring Gull - Adult
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Herring Gull - Adult
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California Gull - Adult
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Herring Gull - Adult
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Thayers Gull - Adult
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Thayers Gull - Adult
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Thayers Gull 3d cycle
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Thayers Gull - Adult
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Thayers Gull - Adult
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Thayers Kumliens - Iceland
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Thayers and Smith

• Neal Smith showed that Kumliens and Thayers
  gulls reproductively Isolated
• Richard Snell tried to replicate.
• data on gulls at Home Bay could not have been
  based on actual observations or experimentation.
• Data on the composition of pairs of courting
  plovers (Smith 1969 table 2) in Home Bay were
  evidently not based on actual observations, as
  Smith had not yet arrived in Home Bay at the time
  those data were reportedly collected.

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Glaucous Gull - Adult
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Glaucous-winged Gull - Adult
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Heermanns Gull - Adult
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Heermanns Gull - Adult
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Identification practice
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Identification practice
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Identification practice
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Identification practice
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Identification practice
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Identification practice
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Identification Intro The small guys

• Bonapartes Gull
• Sabines Gull
• Black-legged Kittiwake

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Bonapartes Gull - Adult
Steve Metz
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Bonapartes Gull First Cycle
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More on the other small ones next time!
George Armistead
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CLADES - GULL PHYLOGENY - Crochet et al. 1999
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White-headed Gull species Larus

• Western
• Glaucous-winged
• California
• Herring
• Thayers
• Glaucous
• Ring-billed
• Mew
• Heermanns

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Hooded Species - Leucophaeus

• Franklins Gull
• Laughing Gull
• Others in Latin America

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Masked Species - Chroicocephalus

• Bonapartes
• Black-headed
• Others in Asia, Europe, South America, Africa.

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Arctic Gulls, Kittiwakes, etc.

• Sabines Gull and Ivory Gull (Xema and Pagophila)
• Kittiwakes (Rissa)
• Little Gull (and Rosss) Hydrocoleus

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Splits and lumps White-headed Gulls

• White-headed Gulls. Pons et al. 2005
• European and Smithsonian gulls will be split.
• Uncertainty over Vega it should be split from
  European Herring as well?
• Thayers Iceland??
• Western Glaucous-winged (not closely related!)

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Liebers et al. 2004. Herring Gull not a Ring
Species.

• Original model.
• One refugium.
• Eventually smithsonianus re-invades Europe and
  contacts Lesser Black-backed.
• All wrong!

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Liebers et al. 2004. Herring Gull not a Ring
Species.

• New data
• Two refugia.
• Atlantic and Aralo Caspian.
• No invasion of Herring Gulls from North America.

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Gulls and Environmental concerns

• They feed in dumps is this good, is this bad?
• Vectors for disease, avian or human?
• High E. coli levels in Half Moon Bay beaches
  what is the root cause?
• Dieoffs of gulls roosting in Half Moon Bay in
  03-04.

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California Gull in Bay Area

• 21,200 in 7 colonies in 2003
• Amazing population boom since the 80s.
• Dumps to blame?
• Largest colony in a dry salt pond.
• Salt Marsh Restoration will flood most Bay Area
  breeders.
• Where will they go?
• Will they be a larger problem on Snowy Plover?

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Life History TheoryA framework for understanding
key characteristics in the life cycle.

• Resources, time are finite
• Trade-offs
• Different allocation of resources (time, energy)
• Ex many young, short life, quick maturation VS.
  few young, long life, slow maturation.
• Examples in the gulls?

• Molt, migration breeding.
• Molt timing, first cycle.
• Large vs small size.
• Arctic vs. mid latitude juveniles.

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Life history theory in practice
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Life history theory in practice
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Life history theory in practice
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Life history theory in practice
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Molt and migration

• Southern Hemisphere wintering range.
• Complete molt in winter.
• Franklins molts wings twice in a year!

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Migration - examples

• Western Gull, north and south.
• Glaucous-winged Gull, south.
• California Gull, west and south.
• Franklins Gull, Neotropical.
• Sabines Gull, Neotropical.

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Migration Franklins Gull
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Heermanns Gull all upside down
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Gull AgesCycles why I like them

• Simplifies
• From one complete molt to the next
• Makes it easier to compare between species.

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How many cycles? 2-3 and 4 Year (Cycle) Gulls.

• Four Year Gulls
• All the big ones and
• Heermanns

• Two Year Gulls
• Bonapartes
• Sabines
• Kittiwakes
• Three Year Gulls
• Ring-billed
• Mew
• Franklins

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So maturation relates to size!
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Ageing techniques

• Know the start and end points
• Primary shape
• Tails and wings can get blacker
• Eyes, bills etc
• Brown wings versus adult wings
• Inner primaries.

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Start and end points (Anchors)
Adult
Juvenile
California Gull
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Juveniles a special case why?
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California Gull Juvenile starting molt. August.
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Primary shape
Pointed juvenile primaries
Rounded older ages
Glaucous-winged Gull
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Primary shape
Pointed juvenile primaries
Rounded older ages
Glaucous-winged Gull
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Primary shape
Pointed juvenile primaries
Rounded older ages
California Gull
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Brown to Black
First Cycle
Second Cycle
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Brown vs. Adult wingsThe inner primaries are key
Second Cycle
Third Cycle
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Soft Part Colors

• Yellow eyed species tend to get the yellow eyes
  in the second cycle.
• Bills become pale from the base.
• Pink or yellow bill bases?

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Hormones and feather color