Osprey Diary 17th April: Egg Q and A

A wonderfully calm and uneventful day today on the osprey nest at Loch of the Lowes, with the two eggs being incubated in the spring sunshine by both parents. We are so pleased to have two eggs (and therefore two possible chances of a live chick this year) but of course we can’t help hoping there might be one more- possibly even laid tonight or tomorrow morning  so keep your eyes open! Today we’re reprinting some of the most commonly asked questions about osprey eggs- for more like these please see our FAQ pages by clicking on the tab at the top of this page.

Q: How many eggs do they lay?

A: Two or three is the usual number of eggs for an established breeding pair. Ospreys tend to start breeding at 3 to 7 years of age.  In the first year of breeding, however, they often fail to breed successfully, and younger birds often start off with one egg, producing two the following year, and hopefully building up to a standard clutch of three.  Rarely four eggs are laid, although these may not all hatch, nor all survive to fledging.

 Q: How far apart are the eggs laid?

A: Osprey eggs are usually laid 1-3 days apart, that is with an average of two days between each, although a gap of up to 6 days has been observed, the whole clutch laid over up to 10 days . 

 Q: How big are the eggs?

A: Surprisingly, osprey eggs are only the size of a large hens or duck egg. 

 Q: Why are the eggs spotted – they don’t seem very camouflaged?

A: Each of the eggs is unique and is a combination of off-white to pinkish or buff background, with mottled dark brown or reddish splotches. Some eggs have a uniform mottled appearance while some can have more of this reddish brown colouration at one end. Most birds of prey have similarly spotted or specked eggs- in fact many British birds do. Though to us they seem to stand out, from a height or distance the outline of these eggs blurs easily and blends them into their background very effectively.

 Q: How long do they incubate for?

A: The general rule is 5 to 6 weeks (35-42 days), the average being 37-39 days.

 Q; Do ospreys, like pigeons, not sit on the first egg laid until others are laid to join it, to ensure they hatch together?

A: You are correct that this is exactly what many bird species such as pigeons do, but this strategy is not true of ospreys: they always incubate from the first egg laid and this is why the eggs usually hatch a day or two apart, in the order they are laid. 

Q; Could ospreys lay two clutches of eggs in one year?

A: No, ospreys never ‘double clutch’ (lay two lots of eggs and raise two broods in one year) unlike many smaller birds. This is because they know that a late laid brood will not have enough time to mature sufficiently to make an autumn migration safely, and these chicks would be highly unlikely to survive. Long lived birds like ospreys will simply wait till next year to try again. This is why nest disturbance by humans of ospreys is such a problem- it wipes out their whole breeding year. Occasionally if Ospreys lose eggs in the first week or so, they may lay more (such as EJ at Loch Garten who laid egg 3 and 4 after her mate destroyed 1 and 2) but not after a whole incubation has been unsuccessful.

 Q; How long can the eggs be left alone?

A: This depends on two things; predators and weather. Obviously any egg unguarded is vulnerable to opportunistic predators, such as crows, pine martins, herons etc.  If the weather is mild, the eggs can be fine for up to half an hour or so, but if it is cold and wet they can quickly get cold. Too much cold would cause the embryos inside to die as they need a very steady temperature to incubate successfully.

 Q; Is it normal for the male to incubate the eggs?

A: Yes, in general both ospreys will tend to the eggs safety, although the female always does the majority of the incubation. In some pairs males never incubate the eggs, and in other pairs males will incubate for an hour or more whilst the female has a break to fly, toilet and eat. The male is the sole food supplier once the eggs are laid.

 Q: Can the eggs overheat?

A: It is unlikely the eggs got too hot (incubation temperature is usually over 30 degrees C) but humidity is also important, and sometimes hot dry weather can make the shells a little tougher than normal.

Q  Do chicks hear outside noises as they develop inside the shell? The female ‘chirrups’ to it so it must hear that?

A: As the chick develops inside the shell, all its senses grow. From my limited experience with captive bred birds, I believe this sense ( hearing) only becomes functional in the last week or so of incubation- it is probably the same for osprey chicks.

Ranger Emma

 

 

 

Posted in Diary 2014 |

Osprey Diary 16th April

First glimpse of the second egg 2014- copyright SWT

First glimpse of the second egg 2014- copyright SWT

What a great way to celebrate our 50th birthday- with the 70th osprey egg! All is well on the osprey nest today after our female laid her second egg at around 2am this morning. Alas I missed it as I had finally gone home to get some sleep, but I got a very excited phone call from our Nightwatch team Ainoa and Kirstin to tell me the good news in the early hours. The centre has been buzzing with visitors today come to see the happy couple on their nest. Here are some lovely photos from our HD nest camera:

The Happy couple with their two eggs- copyright SWT

The Happy couple with their two eggs- copyright SWT

Close up of the eggs this morning- copyright SWT

Close up of the eggs this morning- copyright SWT

Ranger Emma

 

Posted in Diary 2014 |

A Peaceful Day on the osprey nest -mostly! 15th April

It has been a mostly peaceful day on our Loch of the Lowes osprey nest today, thank goodness, so we can all get over the excitement of the last few days! There has been much sharing of incubation duties between the male and female, and no fewer than four fish deliveries to the nest today. There was some aerial action this morning when the male gave chase to some carrion crows who dive bombed the nest- a standard tactic that they use to trick adult birds into leaving tasty eggs unprotected. There was also one intruder osprey around this afternoon briefly, but no serious aggression.

Here’s a stunning photo of one of our Ospreys at Loch of the Lowes by Phil Hannah- copyright.Osprey at Loch of the Lowes by Phil Hannah- copyright.

You will notice the webcams are back up again- techno gremlins successfully banished again- thanks to Michael our IT officer and Stuart from Scottish Communications.

Lastly, thank you to everyone who has phoned, emailed and tweeted us with support for our wonderful volunteer and staff team who did such a great job protecting the birds on Sunday during the disturbance incident. Its is a timely reminder to everyone this Easter to remember all birds and their nests are legally protected, and to keep a safe respectful distance in order not to cause disturbance, and allow the birds we love to breed in peace.

Ranger Emma

Posted in Diary 2014 |

Webcam Offline Temporarily Sorry

HI folks, it never seems to rain but it pours- on top of our human disturbance incident yesterday at the osprey nest yesterday ( see below) , now the webcam is playing up! The problem again appears to be the computer streaming side of things- rest assured we still have great images in the visitor centre and see and monitor the birds. We have a technician working to restore the images to our web audience as soon as possible.

Meanwhile, both bird shave been enjoying the spring sunshine- its been glorious today- and the male brought his mate a large half a pike this afternoon around 4.30pm, taking his turn incubating whilst she went off to eat. All appears to be well with the egg- but will it be joined by another tonight???

Ranger Emma

Posted in Diary 2014 |

Osprey Diary 14th April

Proud New osprey dad- 13th April, SWT

Proud New osprey dad- 13th April, SWT

Our first osprey egg of 2014 was most welcome , laid very early Sunday morning- just in time to help us celebrate 50 wonderful years of the Scottish Wildlife Trust. Our visitor centre as packed yesterday with people enjoying watching the birds incubating their new egg- with both adults taking turns. Charmingly the male seems so besotted with his new egg, he was seen yesterday a couple of times pushing the female off so he could have a go incubating!

Sadly the egg’s first day was not uneventful , however, as many of you noticed around 2pm yesterday  the female osprey was frightened off the nest. She was away for quite a while, and even on her return, she was unsettled and didn’t resume incubation for another 10minutes. We are so very lucky that in this period an opportunistic predator didn’t happen by, and that the weather was gloriously warm so the egg is unlikely to have suffered any damage.

What caused the disturbance was the irresponsible actions of two people who walked into the small area of the reserve that is off limits this time of year to protect the breeding birds. We always welcome responsible users of our reserves abiding by the Scottish Outdoor Access Code, but there are some areas where the legal protection of vulnerable species take precedence for a few weeks each year- as in the area round our osprey nest.

It was the quick thinking and calm professionalism of our wonderful team of volunteers  and staff , which enabled the situation to be resolved as quickly as possible with local police assistance. This highlights the reasons we still have a 24hr, 7 day a week Osprey Nest Protection Watch, staffed by over 70 volunteers- whose hard work is so worthwhile and appreciated.  It shows that even if human disturbance is unintentional, it can cause serious harm to vulnerable species and can cause breeding failure or even nest abandonment. It is vital if the conservation success of the osprey’s UK recovery is to continue ,  that nests are protected.

It also highlights why we have gone to such lengths to provide first class viewing facilities at Loch of the Lowes for the birds- to make it safe, enjoyable, and accessible to all, without disturbing or compromising  the birds. We also help people understand what a safe and respectful distance is from such nests, wherever they are being found or watched.

I have to say I am immensely proud to lead such a dedicated team of people who share in this important osprey protection task, and hope you will join me is sending out a huge THANK YOU to them all for their sterling work this weekend and during the whole breeding season.

 

Posted in Diary 2014 |

Osprey Egg Laid by Moonlight 13th April

Wonderful news here at Loch of the Lowes with out first Osprey egg of the 2014 breeding season laid overnight.  At around 12.30 last night our nightwatch staff noticed classic egg laying behaviour- the bird lying low and panting, and at 12.47 the female stood up to reveal her new egg.  It is just as well the birds have built such a deep , snug cup in the centre of the nest as it was so windy last night, the whole nest tree was rocking.

First Osprey egg of the 2014 season at Loch of the Lowes- copyright SWT

First Osprey egg of the 2014 season at Loch of the Lowes- copyright SWT

 

Since it was laid, the egg has been carefully tended and both birds have taken a turn incubating. The male is particularly keen to have a go- just now he pushed the female right off , insisting it was his turn- this is a fantastic sign that he is bonding with the egg and his instincts to provide and care for it are fully aroused, which bodes well for the future.

What a fantastic treat to celebrate SWT’s 50th anniversary this weekend!!! The staff and volunteers here are over the moon, and we are so relieved that our beloved female is still breeding at her advanced age. Why not drop in today to share the excitement- entry is FREE at all our visitors centres today only.

Posted in Diary 2014 |