Smooth Softshell Turtles in lake Independence nesting now
by Dale Ortlip (source: MN DNR website)
The smooth softshell turtle inhabits large rivers of the central United States, preferring large unpolluted rivers with sandy substrate. The midland smooth softshell (Apalone mutica mutica) is the subspecies recognized in Minnesota. Records of this subspecies are limited to the lower St. Croix River, portions of the Minnesota River, and the Mississippi River below the Twin Cities. Smooth softshell turtle populations have declined in recent years due to river channelization, siltation, and water pollution. This species' ability to extract oxygen from water may make it particularly vulnerable to water pollution. In addition, sandy beaches utilized as nesting habitat by this species can be degraded by humans who recreate in such areas. In particular, waste left behind by humans can attract turtle egg predators, such as raccoons and skunks. Nesting activities can also be disrupted by human activities. Finally, the market for commercially harvested softshell turtles has recently experienced rapid growth. All of these factors have led to the species' status as a special concern species in Minnesota.
Unlike most turtles, the smooth softshell turtle has a smooth, leatherlike, flexible carapace and a long, tubular snout. Females are larger than males, with a carapace length of 16.5-35.6 cm (6.5-14 in.) compared to 11.4-17.8 cm (4.5-7 in.) in males. Females and males also differ in color. The carapace of adult females is tan or brown with irregular dark brown blotches, while the carapace of males and juveniles is a brown or grayish color with scattered, small dark brown dots or dashes. Smooth softshell turtles may be easily confused with the spiny softshell turtle (Apalone spinifera), as the differences between the two species are subtle. Spiny softshell turtles have a rough carapace with spines or bumps along the front edge, while smooth softshell turtles have a smooth carapace which lacks spines on the front edge. Also, the spiny softshell has a lateral projection on the nasal septum that extends into the nasal opening, while the smooth softshell does not (Oldfield and Moriarty 1994). Additionally, the smooth softshell's white eye stripe is more distinctive than the spiny softshell's, and their white chin and throat are unmarked, compared to the splotchy chin and throat of the spiny softshell. When handled, spiny softshells can be quite aggressive compared to smooth softshells.
Smooth softshell turtles prefer large unpolluted rivers, with sandy substrates. They can also be found in lakes, impoundments, and shallow bogs. In Minnesota, the smooth softshell turtle has been found in large rivers with currents which are moderate to fast. They prefer water with sand or mud bottoms, without rocky areas or dense vegetation.
Biology / Life History
Smooth softshells hibernate underwater buried under the substrate. They emerge in the spring and breed in Minnesota from May to June. Male smooth softshells mature in their fourth year, while females mature when they are 7-9 years old. Females nest from June to early July on sandbars and riverbanks with full exposure to sun. Females seldom use beaches which are entirely brushed. They lay 1-33 eggs which are 20-24 mm (0.8-0.9 in.) in diameter and have thick, brittle white shells. Eggs which become submerged from extended rises in water level due to rain or human regulation, do not survive. The eggs require 8-12 weeks of incubation, after which time the hatchlings tear out of their shells using their front legs and egg tooth. The main predators of smooth softshell turtle eggs are skunks and raccoons, while the main predators of hatchlings are fish, turtles, snakes, wading birds, and some mammals (Ernst et al. 1994). Adult smooth softshell turtles in Minnesota have few predators, other than humans.
Smooth softshells eat insects, crayfish, snails, worms, fish, amphibians, clams, isopods, spiders, and some plant material. They catch their prey both in the water and on land. Because of this species' soft exterior, softshells are highly susceptible to desiccation, and must stay near water, even when basking. Smooth softshells travel a great deal based on the seasonal conditions of sandbars, and have large, linear home areas which are dynamic and may change location. Mean home range length for males is around 474 m (0.3 mi.), and that of females is around 1,228 m (0.8 mi.). When smooth softshells are not feeding or basking, they spend most of their time buried in mud or sand in water shallow enough that they can extend their long necks above the surface and get air. Because they are able to extract oxygen from water, smooth softshells can remain submerged for long periods of time.
Conservation / Management
Several threats impact the health of smooth softshell turtle populations. Among them are habitat degradation, pollution, human activities at nesting sites, and overharvest of this slow maturing species. Land clearing and wetland drainage for agriculture, pollution by sewage, and construction of locks and dams have seriously harmed or eliminated populations of smooth softshell turtles (Moll and Moll 2000). Smooth softshell populations can also be damaged by increased run-off and silt caused by changes in the habitat structure near rivers. Because of this, waterways and lands that contain important turtle populations should be protected from human disturbance and pollution through enforcement of best management practices. Areas upstream from turtle populations should be protected, as well, as turtle habitats are subject to degradation and pollution from upstream activities. For smooth softshell turtles to survive, protected areas need to contain basking and nesting habitats, sufficient prey, hibernation habitat, and movement corridors. Minimizing human disturbance at sandy beaches where smooth softshell turtles nest would benefit this species. Human activities can disturb or destroy nests, and debris left behind attracts nest predators. Additionally, wave action from boats can result in erosion of nest sites and exposure of eggs. Nesting females are easily frightened and may stop nesting if disturbed.
Smooth softshell turtles are harvested for meat and they are also at risk of being captured and drowned by gill nets and set lines used for commercial fishing. Because of the smooth softshell turtle's long maturation period, population recovery from these causes of death may take many years.
Other common names for this species include mud turtle and leather back.
Conservation Efforts in Minnesota
The Minnesota DNR funded a study of turtles in the Weaver Bottoms area of the Upper Mississippi River in 2001 to assess management and conservation concerns. The authors indicated that more research was needed, but noted that smooth softshell turtles were rare and probably impacted by commercial fishing and turtle harvest. Since then, the Minnesota DNR revised Minnesota's commercial turtle harvest laws, and smooth softshell turtles are no longer a harvestable species.
Lake Independence Pelican likely died of Highly Pathogenic Avian Influenza (HPAI)
LICA Board Member and Loon Center Rescue contact Angela McLaughlin noticed a pelican at Baker Park was potentially not feeling well because it was not in a normal location (sitting beneath a tree, alone, head tucked oddly). It did perk up and open its wings when she approached, but she felt it must have been earlier on in its symptoms. “I’ve seen the virus move very quickly through birds, so in a matter of hours they can go from being lethargic to hanging their head, swinging their head in circles, and tremors/muscle spasms, to death,” said McLaughlin.
Wildlife Rehabilitation Center states that if you see a bird on the HPAI-affected list that’s acting abnormally, there’s a high likelihood of infection. The list keeps growing and changing as new species test positive, but raptors and waterfowl are the most impacted species so far. Since Lake Independence has a healthy eagle and waterfowl population, that’s something for us all to monitor. Though it’s an avian influenza, they have now found it in the red fox population, as well.
Individual birds may exhibit the following signs of illness:
Inability to fly
Swimming in circles
Trouble standing upright
Loss of coordination
Other signs of HPAI include multiple dead birds in the same location and timeframe. There is no cure for HPAI.
If someone sees a bird acting abnormally, they should reach out to Wildlife Rehabilitation Center for advice at 651-486-9453. Leave a message and the call will be returned. WRC may also be contacted for orphaned and injured wildlife of other species.
If it’s a raptor, it should be taken to The Raptor Center on the U of M campus.
Deceased birds should be double-bagged and put in the trash or buried (away from the water). And they should be removed from the environment quickly. The DNR is NOT coming to collect dead birds, so it’s up to people to dispose of them. The DNR is asking that people call to report birds suspected of having or dying of HPAI. They should call 888-646-6367, get to the right person, and file a report.
This question has been going around a lot, but as of right now, songbirds are not affected.
Angela can be reached at Angela@lakeindependence.org. She is happy to answer questions.
Sandhill Cranes nesting in the wetlands of Lake Independence
PHOTO CREDIT: 2023 Barbara Zadeh
Birds of Lake Independence: Mergansers
by Dale Ortlip
Male left, female right
Female left, male right
Common Mergansers are larger than Hooded Mergansers with a longer, thinner bill and paler sides. Buffleheads are smaller than Hooded Mergansers. Males have a white belly and sides whereas male Hooded Mergansers have cinnamon sides. Buffleheads are smaller than Hooded Mergansers.
The various Merganser species have different plumage, or feathers, but similar body and bill shapes. Their bodies are long, and they have long, narrow bills with a hook at the tip. Their bill is similar in appearance to a cormorant’s bill.
Wooded lakes, rivers; in winter, rarely coastal bays. Mainly around fresh water at all seasons. Summer: on shallow but clear rivers and lakes in forested country; avoids dense marshes and muddy waters. Winter: on lakes, large rivers; occasionally on bays along coast.
forages by diving and swimming underwater, propelled by its feet, stroking with both feet in unison. Finds most food by sight; may swim along surface, dipping head underwater repeatedly until prey is spotted, then diving in pursuit.
8-11, sometimes 6-13. Pale buff. Females often lay eggs in each others' nests. Incubation is by female only, 30-35 days. Young: May remain in nest a day or more after hatching; then they climb to cavity entrance and jump to ground. Female tends young birds for several weeks, but young feed themselves; they may survive even if abandoned quite early. Young are capable of flight about 65-70 days after hatching.
May remain in nest a day or more after hatching; then they climb to cavity entrance and jump to ground. Female tends young birds for several weeks, but young feed themselves; they may survive even if abandoned quite early. Young are capable of flight about 65-70 days after hatching.
mostly fish. Eats a wide variety of fish; also will eat mussels, shrimp, salamanders, rarely plant material. Adult males may swallow fish more than 1 foot long. Young ducklings eat mostly aquatic insects.
Courtship displays of male include swimming very rapidly in circles near female; suddenly stretching neck upward, pointing bill straight up, and giving soft call. Nest site is near water, usually in large tree cavity; also in crevices in rock, in holes under tree roots or undercut banks, or in nest boxes. Occasionally in buildings. Nest of wood chips or debris in cavity, plus lining of down.
Interesting Facts About the Merganser
These ducks are quite interesting creatures, with many unique traits and adaptations. Learn more about them below.
Dropping Ducklings – Just like goldeneyes and wood ducks, some Mergansers nest in tree cavities high above the ground. When the ducklings hatch, they jump from the tree and tumble to the ground! Thankfully, they are quite resilient (and a little bouncy.)
Stealing Seagulls – Lots of seabirds take advantage of the success of other animals, and these ducks often become the victim of this. Gulls will follow a duck as it fishes, then try to steal the duck’s catch before it can swallow it, instead of hunting for their own fish.
Brood Parasite – Not to be outdone, Mergansers sometimes take advantage of other birds as well. Females will lay an egg or two in the nest of another female duck. The other duck hatches the duckling and raises it unknowingly.
They do not make good pets.
Duck hunters call mergansers “fish duck”.
Documented they will eat zebra mussels – but not a preference.
Get the lead out!
Protect our wildlife by switching to non-lead tackle
Most fishing tackle currently available is made of lead. Lead is a toxic metal that is lethal for loons, trumpeter swans, bald eagles and other wildlife. Loons are poisoned when they inadvertently swallow lead jigs and sinkers while scooping up pebbles to help grind their food. About 20% of the dead loons turned in by private citizens died from lead poisoning.
Loons can frequently be seen on Lake Independence
CREDIT: Barb Zadeh
A bird with lead poisoning will have physical and behavioral changes, including loss of balance, gasping, tremors, and impaired ability to fly. The weakened bird is more vulnerable to predators, or it may have trouble feeding, mating, nesting, and caring for its young. It becomes emaciated and often dies within two to three weeks after eating the lead.
The MN Pollution Control Agency has a new public awareness campaign called “Get the Lead Out” focusing on encouraging Minnesota anglers to switch to non-lead tackle. After a seven-year study proving that Minnesota loons winter in the Gulf of Mexico, the state was awarded $1.2 million from the Deepwater Horizon oil spill settlement. The MN Pollution Control Agency is using the money to fund the lead-free educational program, in cooperation with the U.S. Fish and Wildlife Service. For more information, see https://www.pca.state.mn.us/living-green/nontoxic-tackle-get-lead-out
Lead-free tackle from various manufacturers
LICA fishermen can help by switching to lead-free sinkers and jigs, telling your friends about the problem, and encouraging your favorite bait and tackle shop to carry lead-free products. The MN Pollution Control Agency has a list of tackle manufacturers using non-toxic metals:
(Lead is classified as hazardous waste. When you’re ready to make the switch, collect all of your old lead tackle and take it to Hennepin County’s hazardous waste disposal site in Brooklyn Park.)