From the Contact Station September 2023

Miracles and Mysteries

We didn’t believe it at first. One Friday morning in late June volunteer Brent was told by a birder that they had seen crane colts, but no photos. He passed on the information to me. We both thought that was unlikely; the Kiwa had been reopened, the cranes had moved off and there was no further observed nesting activity. Later that day, another visitor stopped to chat. Beth mentioned in passing that they had seen two baby Sandhill Cranes earlier that week. Yes, they had taken photos and were happy to share.  Happy crane dance, documentation!

That evening was the farewell party for Jared Strawderman; I knew most of the staff would be there. In hopes that I’d get a photograph quickly, I saved the news for the party.  While I was waiting for the email, I shared the reported sightings. The looks I got from the faces were like the ones that Brent and I had shared that morning. It just couldn’t be; we were sure nesting had failed. We waited for the photograph and the e-mail arrived about 5:00 pm.  And, as I have done so often, without the photograph attached. Arrrhh. I responded urgently saying ‘we are dying here, photograph not attached, please resend.’  We all went home, after exchanging emails, hoping for the best outcome.

It was thrilling to see the photograph the next morning.   There was Mom and Dad and two tiny Sandhill Crane colts. I immediately shared it with Eric Anderson, our deputy project leader and father of all things crane on RNWR.  One of Eric’s past assignments was monitoring many nesting Sandhills at Conboy NWR, east of us on the other side of the Cascades.  Consulting with others who have studied cranes extensively, our colts were estimated to be ten days old in the June 25^th photo.  We can only speculate since we hadn’t witnessed the whole process of nest creation, egg incubation, and hatching. They must have re-nested quickly after the initial failure.

A little recent history:  Why is this so exciting? Our Sandhill Crane, Antigone canadensis rowani, which spends winter throughout the Vancouver Lake Bottoms, Sauvie Island, through the Refuge, and up into Woodland typically leaves in April to nest in the coastal Islands off British Columbia.  There are two anecdotal accounts of nesting activity in the past.  One observation was by a farm equipment operator on Sauvie Island seeing nesting behavior around 2005. The other is a notation of nesting in the justification paperwork for adding Bachelor Island to the refuge in the mid-1980s.   However, in the last four years now, we have had spring nesting near the Kiwa Trail. The first two years brought forth a colt, both verified to fledging by sightings of a family of three flying in the area in and close to the Kiwa Trail nesting sight.  Last year, it was thought the colt did not survive to fledge, i.e. being able to fly. What happened is unknown, but it might have succumbed to a predator.

So that brings us to this year.  On March 14^th, there was a first observation of the pair of cranes plucking grass and setting it aside in a pile.  This is common behavior as cranes build platform nests, usually in a wet area.  The pair was observed through the end of March around East, West and Middle Lakes of the Hunt Zone, near the hairpin turn of the Kiwa Trail.  It is assumed the cranes started sitting the nest in early April.  It takes 30 days to incubate the egg and hatch a colt.  The female does most of the nest sitting, but the male shares also.  The estimate for hatching was around May 1^st.  The effort failed probably sometime in early May as the pair was seen in mid-May without a colt.  One e-bird account noted at that time “major angst” with the cranes as a Bald Eagle was following a crane near the Kiwa. Later in May, there were several sightings in e-bird that included two cranes across from the Kiwa trail on the auto tour.  On May 26^th, after preparing the trail for walkers, the Kiwa was opened.  The nesting effort had been deemed unsuccessful.

The best protection for a colt against predators is the parents.

One is always with the colt or on the nest.  From egg-laying to fledging (aka flight stage) is 90 days.  Eggs and younger colts are very vulnerable to a variety of predators including coyotes, Great Horned Owls, raccoons, mink and sometimes hawks and eagles.  To protect them, the adults threatened by avian predators will use upright forward, upright stab, and upright kick behaviors. When confronted by a mammalian predator, the typical response is an upright forward behavior where the wings are partially or fully spread, and the bill oriented toward the predator. They might also use a distraction display, a stiff-legged wing-dragging movement away from the nest or nestlings.

What happened that we missed?  Our two baby cranes were not seen (or at least reported) until June 25^th and were within the center of the auto tour. In late May, there were several singular sightings of a crane in the Ruddy Lake area and across from the Kiwa entrance. Probably, they had nested by then deep in the high vegetation and we were seeing one adult that was out foraging.

The presence of standing water with emergent aquatic vegetation is an important characteristic for a nest site.  They generally construct nests in water where floating piles of aquatic vegetation, grass, mud, sticks, and moss separate vulnerable eggs and chicks from terrestrial predators. The Kiwa area was wet enough in the late spring to early summer to support nesting.  For the second nest attempt, the area deep in the center of the auto tour probably looked more promising as the Refuge continued to dry up.  Though the shallow lakes quickly dried out, the small stream-like depressions weaving through the area can stay wet longer and muddy. Even though the fields are very dry, looking across the River S you can see vigorous wetland plant growth indicating some standing water and mud.  Certainly, the adult cranes have been playing in the mud as they are very brown, i.e., dirty, from spreading mud on their feathers which cranes like to do.

It was exciting to see two colts following the adults, on June 25th.  Careful observation ensued.  Now that they were within the auto tour route, we kept the sightings quiet in the hopes the colts would have the best chance of surviving.  A colt without a protective parent with them is a prime target for those predators.  The last thing we wanted to see was disturbance that separated the colt from the parents. We did get reports of two Sandhill Cranes, but because the vegetation was so high, the colts were not being seen.  The reports were literally head counts because that was all you could see.  Indeed, trying to find parents AND colts when we knew they were there was very hard, requiring a lot of patience and time. Sadly, the last reported sighting of two colts was July 9^th.  Predation is certainly a possibility, but in addition, sibling aggression is well known in colts beginning on day two of hatch.  Sibling aggression may be one reason why, even though cranes typically lay two eggs, often only one bird is raised to fledge. It takes an abundance of food to mitigate aggression.

The adults must have re-nested quickly.  Trying to calculate back to likely nest start, we come up with a date of about May 16^th and hatch around June 16^th given the estimate of the first seen colts as about 10 days old. There was a lot of walking around in the center of the auto tour. The family was verified at different times, seen from the blind on Rest Lake and also from the road back in Canvasback Lake. On July 21^st, the remaining colt was with one adult when the second parent flew in about 100 yards away and began calling.  The colt immediately moved toward the parent as it repeatedly called and the other parent followed.   It takes our cranes about 65 to 70 days to fledge from hatching.  Our estimate was somewhere around August 22^nd for a colt flight.  It was an anxious time, because once they can fly, they are a lot safer, being able to evade predators.

On Monday, August 21^st the crane family was sighted on north Quigley Lake, that small patch of water way to the north where some shorebirds were hanging out.  It is not likely they walked there from the Rest Lake area.  A long movement out of the immediate nesting area usually denotes fledging.  On the morning of Tuesday, August 22^nd, the crane family was walking in a stream depression toward the road at about #3. They stopped about 50 yards out, seemed to be having a discussion (forgive me the flight of fancy here) and then took off in flight across the road and along the tree line heading in the direction of Rest Lake.  My photo was taken through the car window so is not the best, but it documents flight out of the Quigley Lake area.

There are two more adults hanging out this summer.  They have been frequently seen in Big Lake near the bottom of the tour route.  They like to hang out with the deer feeding in the wet area along the canal. We have given some thought about these two.  Could they be previous offspring of the mating pair?  Maybe they are two young adults not yet ready for nesting?  Studies of the Conboy cranes indicate they usually reach about three years before initiating mating.  The larger general crane population across the US ranges from 2 to 8 years before starting to mate.  Cranes do like to migrate and move around together in small groups, often related.  Could we have the beginnings of something bigger for future generations?  One important note, the area of the River S and Hunt Zone has a fairly consistent hydrology, being inside dikes and not subject to fluctuations as in surrounding areas subject to tides and river rise with spring water flows.  Being able to build a nest in a stable wet environment is more desirable for the cranes.  Let’s hope they continue to find the area suitable, and we will see more cranes nesting in the future.  Meanwhile, keep an eye out for our crane family.  The new colt will stay with the adults for at least the first year. Big thank you to Beth and Rick Jordan for their observations and photos.  And thank you to Eric Anderson for sharing his vast crane knowledge and reviewing this report.

 

Another Visitor Observation:  Also keep an eye out for our otters.  A group of nine was spotted skittering across the fields north of the Contact Station in late August.  They were making their way from Lake River to the canal along the first leg of the road toward the hunt gate.  Later that day, visitors reported them chasing frogs and turtles in the canals and having a meal of frogs.  Well, we could use some Bull Frog control.  But more surprising was the report of another visitor later in the day that the otters were continuing to chase turtles and ducks.  She had captured the process on video.  Unfortunately for the duck, it did get eaten by the voracious otters.  I saw the video, sadly.

Water is again being pumped into the hunt zone from Bower Slough.  It will take a while to reach the auto tour ponds.  Flow is dependent on river level and can only be pumped with the high tides right now.  That should bring more sightings of our hungry otters.  Fall migration is starting.  Enjoy the seasonal changes.

-Susan Setterberg, Contact Station Volunteer