Bats (wetland) - Bats are crepuscular mammals (active at dawn or dusk), which make up 20 percent of all mammalian species. At Bluff Lake we have two different species, the Big Brown Bat, and the Little Brown Bat. These species are most common in urban environments because they have the ability to roost in many different locations. These species are insectivores whose diet consists of moths, wasps, mosquitoes, gnats, midges and other insects. Bats play an important role in the ecosystem by acting as pollinators, seed dispersers, as well as insect population control. We are happy and fortunate to have them at Bluff Lake!
Big Brown Bat
Little Brown Bat
(wetland) - Bluff Lake's beavers live along Sand Creek and they chew down cottonwoods throughout the site (as seen in the photo to the right, taken December 2008). Beavers are mammals and have several adaptations
that allow them to spend most of their time in water, including a gland that excretes an oily substance that waterproofs their fur, an extra, clear eyelid that allows them to see when under water, and valves that close to keep water out of the nose and ears.
More information can be found at enature.com and wikipedia.org.
Blue Grama -
Blue grama is the Colorado state grass. It grows naturally
all over the United States. You will find blue grama
at Bluff Lake growing in bunches along the trail.
On the end of the stalk is a line of seeds that look
like eyelashes. These seeds provide a great food source
for animals in the winter when there is little food
to be found.
Cattail - You can't
miss the cattails that grow thick in the wetland area.
In the summer they can grow to be over 7 feet tall.
The fuzzy brown part on the top is really thousands
of seeds that burst open in the winter, sending seeds
flying in the wind for miles. The cattails provide
a great hiding place for many animals. Look flattened
areas of cattails where the deer have made beds.
Coyote (prairie) - Coyotes
look very similar to wolves, but they are much smaller.
Their coat blends in with the various shades in the
prairie. Coyotes are mostly active during the day when
they are hunting for small prey like rabbits and small
rodents. When coyotes hunt in groups they can catch
much larger prey, like mule deer.
Click here to access more information from Denver's Department of Parks & Recreation about coyotes, their role in the urban ecosystem, and hazing them in your backyard or neighborhood. Where BLNC agrees that coyotes should be hazed in housing areas, please refrain from hazing them at Bluff Lake unless they are acting in an aggressive manner.
Eastern Cottontail Rabbit (prairie
and grassy wetlands) - Cottontails get their
name from their fluffy white tail. they can live in
a variety of habitats, but need to be able to dig burrows
for their homes. Cottontails are herbivores that eat
grasses and flowering plants. In the winter they eat
twigs and small trees. In the spring and summer they
can have up to 8 litters with an average of 4 young
per litter. The young are ready to leave their mother
within 2 to 4 weeks.
Great Horned Owls – Great Horned Owls are typically 18-25 inches long with a wingspan of 36-60 inches and weight 32-60 ounces. As is typical for raptors, females are generally 10-20% larger than males. Great Horned Owls start their mating activities in December, nesting in January and February. The female usually lays two eggs, but sometimes up to four. She does all the incubation, which last an average of 33 days. The male hunts at night and brings food to the female. At 6-7 weeks after hatching, the owlets leave the nest (before they can fly) to sit on the tree branches and then start flying at 9-10 weeks. The parents will continue to feed them well into the summer. By autumn the young owls are off on their own, but have been known to hang around until the parents start mating behavior again in December. The young will not mate for a couple of years. Please click here for more photos of Great Horned Owls and to hear recordings of the sounds they make.
Mosquitoes (wetland) – Mosquitoes live in two different habitats, during their larval phase they live in the water (providing nutrients for many aquatic creatures) and during their adult phase they live on land (providing an important food source for birds, bats, and dragon flies). Mosquitoes can also be considered home bodies, most of the time they remain within one mile of their breeding site. Believe it or not, mosquitoes are primarily nectar feeders; many people do not realize that not all mosquitoes are interested in mammalian blood. Only female mosquitoes need mammalian blood to ensure that they receive the necessary nutrients for producing offspring.
Even though we realize the ecological importance of mosquitoes for the animals at Bluff Lake, we also want to keep our visitors happy too! We strive to achieve this balance through our mosquito management program. We have adopted a comprehensive approach to mosquito control that includes the spreading of the natural larvacide BTI (a bacterial toxin that infects and kills mosquito larvae, but does not harm other wildlife), and the installation of bat boxes. If you would like to help out at your home, think about creating bat box in addition to getting rid of any standing water around your house.
Mule Deer (prairie) -
Mule deer get their name from their large ears that
are especially useful for hearing predators that may
be approaching. In the summer mule deer coats are reddish
brown that changes to a darker gray in the winter. The
young (fawns) are reddish with white spots. Only the
males have antlers. Antlers are different than horns
in that they fall off in the late winter and grow back
every fall. Their antlers are made of fast-growing bony
- The Plains cottonwood is a native Colorado tree
that only grows close to a water source. You will
find these trees along the trail as you approach the
lake and by Sand Creek. Their leaves are very distinct
and look like an upside down heart. In the spring
they release thousands of white fluffy leaves that
look like cotton. This tree provides a great nesting
place for many birds, not to mention that it is the
favorite food of our
resident beavers. Look for trees
that have been chopped down by the beaver to eat or
make their home. These trees will have a distinctive
point, like a pencil.
Prickly Pear Cactus -
You can find this plant growing along the hill throughout
the refuge. This plant’s fruits is a great food
source for many animals as well as humans. People
have also eaten the stem of the plant, the green fleshy
part. The spines are actually the leaves. By using
this shape they conserve water which allows them to
live in drier climates.
Rabbitbrush - The
rabbitbrush are growing strong on top of the bluff
in the gardens as well as other dry areas of Bluff
Lake. This plant makes a great shelter for rabbits.
Not only will they make their homes underneath the
shrub, they will also eat the flowers, leaves and
even bark in the cold winter months. The flower blooms
later in the summer and has a very strong scent that
attracts many insects, including butterflies and bees.
Raccoon (wooded wetlands) - Raccoons are omnivores (eat meat and plants) that can eat almost anything. They are active at night, but don't have a great sense of sight. They use their sense of touch to find their food. Many people think they wash their food in water, but the water is used to help them feel things more clearly. They live in hollow trees, caves or in burrows created by other animals. They have five fingers that leave a print that looks like little human hands.
Red-eared Slider (wetland) - These turtles get their name from the red coloring on their head, but the red spots are not their ears. They are called sliders because of their tendency to slide off rocks and logs when startled. Turtle shells are made of keratin, the material that makes up our nails. Their shell grows along with the turtle inside. Many turtles are omnivores, eating insects and small fish when they are younger so they have plenty of protein to grow. As they get older they eat mostly vegetarian.
Red Fox (wetland) - The
red fox is about the size of a large cat or small dog.
Red foxes can be a variety of colors, from black to
gray to red. However, all of them have a white-tipped
tail. Red foxes are mainly carnivores that will occasionally
eat berries and fruit if prey is scarce. Foxes are crepuscular
(active at dawn and dusk) or nocturnal (active at night).
during the winter they become more active in the day
when it is warmer.
Striped Skunk (wetland and prairie) - Skunks get a bad name because of
their bad smell, but skunks only release this odor when they are
threatened. They will stamp their feet and raise their tail as a warning
before the spray. Many animals will stay away from skunks to avoid the bad
smell, but the Great-Horned Owl, who can't smell very well, will often calls
them dinner. Skunks are omnivores (eat plants and meat) and eat a wide
variety of food, from mice and eggs to berries and fruit.
willow wreath photo by Linda Broeren |
Willow - There are
many types of willows that grow at Bluff Lake. The
red stemmed ones that grow close to the lake are narrowleaf
willows. The ones growing along the straight section
of the trail by the lake are crack willows. Peachleaf
willows also grow in the area. All of these trees
make great shelter and food for animals. Deer will
eat the branches in the winter and beavers dine on
these trees all year long.
Yucca - Yucca is a
plant that is found only in the four corner states
(CO, NM, AZ, and UT). At Bluff Lake you will find
it along the bluff in great numbers. Yucca have sharp
and sturdy leaves that stick around all year. In the
spring they have a stalk of pink and purple flowers
that many insects and animals love to dine on. Be
sure to visit in May when the blooms are full!
yucca photo by Sue Schafer