Signs of Spring

  Our total rainfall to date is 101", approximately 40" above our normal yearly total!  The rainy season isn't over yet!  However, temperatures were a lot colder this week, and we got about an inch of new snow.  Despite the colder temperatures, signs of the approaching Spring are happening! 

American Robin - Turdus migratorius

This robin is all puffed up in his natural down jacket!  The trapped air between his feathers keeps him warm on snowy days!  Robins are one of the first birds to return to our neighborhood, from their winter habitat.  There were big flocks, of 20 to 40 birds, busily feeding on worms and grubs on the ground.  Apparently some flocks number in the hundreds, and even in the thousands!  I've never seen that many here, as there isn't enough food to sustain that many birds.

    Robber Fly - Laphria sacrator spp.                         Bumblebee - Bombus sp.                        

I revisited that blooming Manzanita and got these pictures of the insects that were feeding on the blossoms.  It turns out that there were Bumblebees there, along with a new kind of fly that I'd never noticed before, a Robber Fly!  

Robber Flies are true flies, and only have ONE pair of wings.  Most other insects, including bees, have two pairs of wings.  They are called "robbers" because of their notoriously aggressive predatory habits.  They will wait and ambush all kinds of insects, including Bumblebees!  Notice the difference in the position of the eyes on the head, as compared to the eyes of the Bumblebee.  Robber Flies are one of the first insects, besides Bumblebees, to show up in the Spring.  Probably all those yellow and black hairs keep them warm in these cool temperatures!  

The Bumblebees that you see out at this time of year are the females.  They are out foraging for nectar and pollen to start their colonies!  The colonies are made in tussocky grasses, small abandoned rodent burrows, or at the base of shrubs.  Once the queen picks a site, she forms a wax "honey pot" and fills it with regurgitated nectar (honey).  She then collects pollen, forms it into a ball, lays her eggs on it, and then covers the whole ball with wax!  She then "broods" her eggs, like a bird, for 4 days, until the eggs hatch into larvae!  Once hatched, the larvae feed on the pollen ball for 4-5 weeks, form a cocoon, pupate, and turn into adults!  A Bumblebee colony usually numbers about 50 in population.  At the end of the season, the queen lays unfertilized eggs, that turn into males, and lays a few special fertilized eggs that turn into new queens.  The males hang out for a few days in the colony, and then leave never to return.  These are the Bumblebees that you see spending the night in flowers!  The new queens leave the colony, mate with one or more male Bumblebees, then hibernate over the winter!

Hairy Woodpecker - Picoides villosus - and gall with grub
Wild Rose Bush with rose hips and galls

One morning I was thrilled to see this Hairy Woodpecker pecking away at the galls on this rosebush!  I'd never seen that before!!  Usually I've seen Hairy Woodpeckers foraging on the trunks of trees for insects!  After he (Male Hairy Woodpeckers have red feathers on their heads and females don't) flew away, I inspected the galls and found this open one with a grub inside! 

Galls come in a wide variety of shapes and sizes. Galls are formed by insect/mite feeding or egg-laying activity. Either mechanical damage or salivary secretions (introduced by insects and/or mites) initiate increased production of normal plant growth hormones. These plant hormones cause localized plant growth that can result in increases in cell size and/or cell number. The outcome is an abnormal plant structure called a gall.  Inside the gall, larvae feed on the gall, pupate and emerge out as adults, over a period of several months!  These larvae are what the Hairy Woodpecker was eating! 

Pocket Gopher - Thomomys bottae - surface tunnel and dirt mounds

Now, finally, the answers to the underground burrow questions!  

There are several local animals that live almost exclusively underground, such as Pocket Gophers and Moles.  They are usually not severely affected by heavy rains 
for several reasons.

 They usually dig their living quarters deeper than 1 meter underground, where the rain doesn't usually penetrate.  They usually make the entrance to their den on a slope, where rain doesn't pool up.  They usually plug the entrances when it's very rainy to keep the water out.  In some cases they even dig a separate sump, for excess water to sit in and drain!!  

I heard some frogs croaking this week before it got cold!  
It made me wonder where are all the reptiles and amphibians?  How do they survive the winter?
Check back next week for the answers!

Early Bloomers!

Although mainly rainy, we did have some sunny days this past week, which caused a few local plants to blossom profusely!  Pollen was in the air and there were a few insects buzzing around!

Willow - Salix sp.

After many months of having colorful but bare branches, the local willows have burst into bloom!  Willows are dioecious, and have separate male and female plants!  Right now both male and female plants are in their "Pussy Willow" stage.  Their soft silvery hairs help keep the developing reproductive parts of the plant warm!  Unlike most "non-attractive" (not bright in color) flowers, willows are insect pollinated.  The female flowers will produce a large amount of strongly scented nectar, and the male flowers will produce a ton of pollen! We'll just have to wait and see what insects they attract!

Pussy Willows - Salix sp.

Alder - Aldus sp. 
the male catkins

Alders are monoecious, and have both male and female parts on the same tree.  The yellow catkins above, are the male flowers of the alder.  The dark brown cones below, are the female flowers of the alder!  Unlike the willows, alders are wind pollinated, and do not depend upon insects for their pollination!

Alders live in a symbiotic relationship with the bacteria Frankia alni.  This bacterium lives underground, in the root nodules of the Alder.  The bacterium absorbs nitrogen from the air and makes it available to the Alder!  In turn, the Alder provides sugars to the bacterium, which it produces through photosynthesis!  Thus this symbiotic relationship improves the fertility of the soil!

the female cones 

Tree Manzanita - Arctostaphylos sp.

I was also surprised to find some Manzanitas in bloom!  Manzanitas are common, local, woody, evergreen plants, ranging from 7"-20' in height!  They have "perfect" flowers, meaning each flower has a male and female part.  They are insect pollinated, and use nectar as an attractant.  Although I did see some large, black bodied bees feeding on the nectar, I failed to get a photograph.  Hopefully I will next time! 

Manzanita - Arctostaphylos sp.

Earthworm - Phylum Annelida

Earthworms have been showing up in the puddles from the rain!  I haven't seen lots of them, just a few here and there.  I always thought that earthworms drown in the rain, but recently found that to be a myth!  Earthworms need to be moist, because they breathe through their skin!  They come above ground when it rains, because they can travel farther distances, when it's wet, without drying out!  Earthworms don't have feet, but they have groups of tiny bristles on each body segment. These bristles
move in and out to grip the surface, as a worm stretches and contracts its
muscles to push forward or backward!

Next week I'll get to the other questions I posted last week!  We're in for another batch of rainy weather, so the questions still apply! Thanks!

Here's the questions:

I wonder how all the underground 

mammals fared during this past rainy week.  

Did their burrows get flooded?  

How far down do they dig their burrows?

The North Yuba River Critters

Due to heavy rain and warmer temperatures, the 
North Yuba River was bookin' this week!  
In seven days we got  13" of rain, plus LOTS of snowmelt, 
which made for a very swollen river!  At one point, the river was moving at a rate of 16.76 cubic ft. of water per second!!! 

               Rock Creek on Thursday & Rock Creek on Saturday 

How were all the river critters affected 
by this sudden change?

Today, I walked down to an area on the river, that typically gets flooded 
when the river is high.  It's been 2 days since the river crested so the water has receded somewhat.  Just as I hoped, there were Dobsonfly Nymphs 
(or Helgrammites) in some of the newly created landlocked ponds!    

Dobsonfly Nymph - subfamily Corydalinae

I found this one in a silted pond, and watched him climb out of the water!  
They need lots of oxygen, and my guess is that he was looking for the river!  
He has only 6 legs, all the other appendages are gills, through which oxygen is 
absorbed from the river water!  Normally these nymphs live on the rocks in the 
super oxygenated white water of a river.  They live underwater for up to 2 years, 
feeding on other aquatic insects, before they molt and fly away as an adult.   

Great Blue Heron - Ardea herodias  & Helgrammite & Weasel -Mustela erminea

I found these large bird tracks in the bottom of the same silty pond!  
They might be Great Blue Heron tracks!  Perhaps the heron was feeding on 
landlocked fish and aquatic insects!  In times of high water, fish will try to 
stay on the bottom of the river, behind rocks.  Sometimes this works, 
but sometimes they get swept away by the force of the water.  
Some of them may have ended up in this pond!

The unusual tracks, on the right, I found in a moist depression that had 
been a pond.  I think the long thin ones, with lots of tiny foot prints, might 
be helgrammite tracks!  Perhaps they were heading for the river after their 
pond diminished!  There are also some bigger footprints in the mud.  
They might be weasel tracks!  Maybe the weasel ate the nymphs!

River Otter - Lustra canadensis

The absolutely most exciting tracks I found were these River Otter tracks!!!  
I've never seen one in person, so these tracks were super cool to find!  
They traversed along the edge of a pond and then onto a field of boulders, where I lost the track.  When the river is a raging torrent, River Otters have trouble catching fish in the swift, murky water, so they come on shore.  

Their main food is fish, but will also eat crayfish, molting ducks, frogs, newts, aquatic insects, and garter snakes.  They are not proficient predators on land, but they occasionally eat voles, hares, and beaver kits. They do not normally chase after fish, but use surprise attack to catch them!  

Underwater they can, hold their breath for 4 minutes, dive down to 60+ feet, swim at 6-8 mph, and travel up to 440 yds. in distance!  They usually travel from 
1.5 to 3 miles in a normal day,but have been known to travel as much as 26 miles!
They can handle the cold river water, because they have a layer of 
insulating fat and a thick undercoat of dense fur.

Usually male River Otters lead the life of a bachelor, except when they are 
looking for a mate.  The females raise the kits on their own, usually in an underground burrow, that has an underwater entrance.  Males will den in a 
hollow log, under a rock or driftwood pile, or in abandoned animal burrows.

River Otters can be 33-52 in. long, and weigh up to 6 lbs.

I wonder how all the underground 
mammals fared during this past rainy week.  
Did their burrows get flooded?  
How far down do they dig their burrows?
Do earthworms drown in the rain?
Check back next week for the answers.

Dead Skunk in the middle of the Road!

This week the rainy weather warmed up my neighborhood, melted all the snow, 

and made the river rise!

A few local animals came out of their 

winter dens and had a look around!

Striped Skunk - Mephitis mephitis

Unfortunately a Striped Skunk was hit by a car on our road, 
and died this week.  Apparently, their biggest enemy is moving cars.
Many skunks die every year on our roads and highways.
Please "Brake for Wildlife" when you're driving! 

Male Striped Skunks have just started to "surface" in my neighborhood.  They have been sleeping in an underground den during the past few months of winter. In February and March, they are out searching at night for a female to mate.

Skunk dens can be in an abandoned ground squirrel or fox burrow, or under a woodpile, rock pile, cement slab, front porch, or in a hollow tree.  
Skunks use their dens year-round.  Skunks will often share a den with 
other skunks.  They don't hibernate, but go into a state of torpor, in which 
their body temperature drops and they fall into a deep sleep.  
To stay warm during winter weather they plug the entrance to their den 
with dry leaves and grass.  

The highly potent musk of skunks, keeps most predators away!  
When approached by a predator, they raise their tail, then they 
stamp their front feet vigorously and hiss and growl.  
If those actions don't deter the predator, they will quickly present their 
hind end and spray musk. They can spray up to 12 feet away, with accuracy!  
Most predators don't come back a second time, once they've been sprayed!
 
Skunks have poor eyesight, but like many nocturnal animals they have highly developed senses of hearing, touch, and smell.  They are omnivores, and eat mice, gophers, voles, rats, birds & eggs, beetles, beetle larvae, caterpillars, fruit, nuts, carrion, bird seed, some garden produce, and even pet food!


Striped Skunks measure 22"-32" + a 10"-13" tail.
They weigh 8+ lbs.

I was so happy to see a Chickaree out and about!
He was busy looking for food in this warmer weather!

At this time of year he is also looking for females to mate, like the skunk!

Nocturnal animals can see a LOT better than 

we can at night because:

1)  Their retinas are packed with Rods and have few Cones. 

Human eyes have way more Cones than Rods.

Rods can sense very dim light, but no color.  This gives them better 

perception of edges, movement, and silhouettes in dim light.

Cones account for color vision, but only in bright focused light. 

Some animals do see some colors, but most, even in daylight, 

only see shades of black & white.

2) Unlike humans, most nocturnal animals also have a mirror like layer, 

the tapetum, behind their retina. This reflects light back through 

the retina, and enhances their night vision.

3) Nocturnal animals have wider pupils, than humans, that lets in more light!

The river is racing along!  

What do fish do to keep from being swept downstream? 

What do fish eat in the winter?  

Do River Otters move to streams for the winter?

Check back next week for the answers!