Class notes
Migration and Dispersal of Birds
- Course
- Institution
Patterns of Migration, Orientation, Compass Mechanisms.
[Show more]
Seller
Follow
jemradford011
Content preview
BirdsWeek 9
Chris Foster
Migration and Dispersal
Residents; non-movers/ risky [cold winters] migrate at high latitudes.
Migration; regular seasonal movement between breeding and wintering grounds
- Artic Tern; 11,000 mile/ feeds en-route
- Risky; tradeoff with overwinter mortality
- Obligate; annual migrants [summer visits = swallow]
1. Survival; some die, but most survive = higher reproducing effort
2. Physiology; higher O2 intake/ diet to gain fat [50% body weight]/ need to increase
fat sources when they run out
3. Evolution; occurs in multiple orders, evolved independently.
a. Climatic change
b. Lac of needed resources
c. Seasonal interspecific dominance reactions
d. Seasonal intraspecific dominance reactions [forced out by other species]
e. Seasonal tracking, fruit/nectar.
4. Experiments;
- Emlen, 1966; measured Blackcap direction in orientation cage/ Blackcap from W.
Central Europe go SW// hybrids go south [selected against]
- Mechanisms in place but resident species = lower migratory anxiety.
Dispersal: movement between breeding sites [species range shift]
Philopatry; site faithfulness [breed and non-breed season] and stopover migration routes.
Local movement; within the territory/ home range
Nomadic/ Irruptive movement; usually some direction to random movement/ Boreal
species into residential areas.
Patterns of Migration;
- No always long distance round trips/ seasonal movements/ N-S/ Spring -autumn
- Vertical migration = altitudinal gradients
- Types;
1. Facultative; Blue tit, move
multiple times
2. Obligate; Robins, move
between 2 areas
3. Nomadism; not returning to home range
4. Partial Migration; not all individuals migrate / tufted duck spreads from core
range.
- Double breeding; N American Species = migrate N to breed/ migrate S to breed/
migrate to wintering grounds
- Altitudinal; issues with climate change
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller jemradford011. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $5.21. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
75323 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now