1. Part 5 – Avian Life Histories
Bird Sex Chapter 14

2. Gonads genitalia typically internal
Paired testes in males
1 ovary in females (left side)
2 ovaries typical of many raptors
500 to several thousand primary oocytes
Testes & follicles dramatic size changes
Affected by FSH & LH
Follicle Stimulating Hormone & Luteinizing Hormone
Produce testosterone & estrogen
FSH – regulates gamete formation in tested & ovary
LH – regulates hormone secretion in testes & maturation of ova

3. Sex Chromosomes Females = heterogametes (ZW) Males = ZZ
Inactive W sex chromosome
Active Z sex chromosome
Males = ZZ
Female’s ova determines sex of young
Female’s seem to be able to adjust sex ratios in clutch!

8. Figure 1. The sex ratio in relation to hatching order in populations in
(A) Montana
(B) Alabama  

9. Sperm Production At night when cooler
Stored at distal end of vas deferens; ~4° C cooler than body

11. Ova Maturation Oocytes present at hatching Ova by 2 months of age
Add yolk in week prior to ovulation
Time varies by spp. (4 to 16 days)
Each structure labeled “F” is an egg (center) with yolk developing around it

12. This female House Sparrow (Passer domesticus or HOSP ) was caught on March 23, 2008, and dissected. (HOSP are not protected under the federal Migratory Bird Treaty Act, as they are a non-native, invasive species.) This female had already laid four eggs in a nestbox. You can see the fifth egg in the oviduct, forming a lining over the egg yolkd and egg white. A sixth and seventh egg are forming with a yolk in the center of the photo. To the left are another 15 or so smaller "seed" eggs. The female HOSP can cut off this string when she completes a full clutch (HOSP generally lay 1-8 eggs per clutch.)

13. Fertilization Occurs at infundibulum After cloacal kiss
No phallus in most
Sperm swim to top in <30 min
Viable for 1-2 weeks
Record = 72 d in chicken

14. Harlequin Duck  & (B) African Goose, 2 species with a short phallus and no forced copulations, in which females have simple vaginas.
(C) Long-tailed Duck & (D) Mallard, 2 species with a long phallus and high levels of forced copulations, in which females have very elaborate vaginas (size bars = 2 cm).
] = Phallus,
* = Testis,
open star = Muscular base of the male phallus,
> = upper and lower limits of the vagina

15. Development of Embryo Moves thru oviduct in ~24 hours:
Albumen (3-4 hrs)
Egg membranes (1 hr)
Shell (20 hrs)

17. Albumen – Magnum
Membranes – Isthmus
Shell – Uterus
Egg colors

18. Egg Composition Yolk = food supply Albumen = H20 supply Shell
21-36% lipids
16-22% proteins
Albumen = H20 supply
90% H20
10% protein
Shock absorber (T & jarring)
Shell
Protection (CaCO3)
Thousands of pores = gas exchange

21. Egg Laying
~1 egg per day in most

22. Vary in:
Shape
Size
Color
Number (lots of interest)

23. Determinate Layers – lay a fixed #
Indeterminate Layers – try for set # in nest
Flicker laid 71 eggs in 73 days

24. Exams Song portion of lab final on this Thursday Lecture Exam #3
Monday - April 30
8 a.m. in this room