Black-headed Grosbeak - Pheucticus melanocephalus Steller's Jay - Cyanocitta stelleri Clutch Size: 2-5 eggs/2-6 eggs
Incubation Period: 12-14 days/16-18 days
This week I checked on all the nests I've been watching for the past month, and found 5 more of them occupied! I also found 2 new cavity nesting birds! All of a sudden the birds are incubating their eggs! Why now? I thought that the nests I've been watching were completed a month ago. Maybe not. Maybe it takes a month to complete a nest according to the birds' standards! Maybe the courtship and mating period is a lot longer than I thought it was! I don't know the answer, but I am thrilled to see all the female birds on their nests! I can't wait to see the baby birds when they hatch in another week or more!
American Robins - Turdus migratorius
Clutch Size: 3-5
Incubation Period: 12-14 days
Incubation Period: 12-14 days
Cliff Swallows (male & female on right) - Petrochelidon pyrrhonota
Clutch Size: 1-6 eggs
Incubation Period: 10-19 days
European Starling - Sturnus vulgaris Violet-green Swallow - Tachycineta thalassina
Clutch Size: 3-6 eggs/4-6 eggs
Incubation Period: 12 days/14-15 days
Who eats Lizards & Snakes?
OK, so it's warmed up for good and the reptiles are active! I saw the two mating Mountain Garter Snakes in our garden! Unfortunately, I found the Pacific Gopher Snake and the Mountain Garter Snake (top right) dead on the highway. The little Spiny Lizard was climbing on a bridge! Who do you think would be eating them?
Here are a few of their main predators:
Snakes Lizards
other snakes other lizards
hawks hawks
river otter weasels
crows birds
owls snakes
Western Tanager Male Bullock's Oriole Male Evening Grosbeak Male
Piranga ludoviciana Icterus bullockii Coccothraustes vespertinus
Sexual Dimorphism in Birds
Dimorphism is a distinct difference in size or appearance between the sexes of an animal. It occurs in birds, mammals, reptiles, insects, amphibians, and even plants!
In most birds, but not all, the male bird is usually larger and more colorful than the female bird. The row of birds above are the male birds and the row of birds below are the female birds, of the same species. Immediately you can see how more colorful the male birds are!!! Why are they so different? Colorful males attract mates. A plainly colored female is less obvious to a predator, on a nest full of eggs.
Studies have shown that most female birds prefer brightly colored mates! Recently it's been discovered that birds can see more colors than we can! They can see all the colors we see, plus ultra-violet light! It turns out that some birds have special ultra-violet markings that we can't see, but birds can!! Even when it appears to us that both the male and female birds have the same coloring, the male might have ultra-violet markings that are visible to a potential mate!
The bright colors of male birds are also indicators of the birds' health. Studies have shown that male bird color is lessened when they are in poor health! This would indicate to a female bird that the less colorful male wouldn't be a good choice for a mate.
Color is also used in contests between males, over mates or territory. Conspicuous colors can help show that an area is already occupied, and the occupant is in good condition and prepared to fight!
Western Tanager Female Bullock's Oriole Female Evening Grosbeak Female
Piranga ludoviciana Icterus bullockii Coccothraustes vespertinus
The locust trees are almost finished blossoming! They are losing their petals by the thousands daily. What is this bird going to eat next? Can you guess what kind of bird this is?
Check back next week for the answers!
Hopefully, the Black Bears might show up
and the river might slow down!
Maybe I'll even see some baby birds!
Canada Goose and Goslings - Branta canadensis
No comments:
Post a Comment